Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

77 files changed, 11933 insertions, 0 deletions

diff --git a/dom/bindings/parser/tests/test_any_null.py b/dom/bindings/parser/tests/test_any_null.py
new file mode 100644
index 0000000000..e76935d005
--- /dev/null
+++ b/dom/bindings/parser/tests/test_any_null.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DoubleNull {
+              attribute any? foo;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_argument_identifier_conflicts.py b/dom/bindings/parser/tests/test_argument_identifier_conflicts.py
new file mode 100644
index 0000000000..b6d6034516
--- /dev/null
+++ b/dom/bindings/parser/tests/test_argument_identifier_conflicts.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface ArgumentIdentifierConflict {
+              undefined foo(boolean arg1, boolean arg1);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_argument_keywords.py b/dom/bindings/parser/tests/test_argument_keywords.py
new file mode 100644
index 0000000000..bbed33df92
--- /dev/null
+++ b/dom/bindings/parser/tests/test_argument_keywords.py
@@ -0,0 +1,22 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+    interface Foo {
+      undefined foo(object constructor);
+    };
+    """
+    )
+
+    results = parser.finish()
+    harness.check(len(results), 1, "Should have an interface")
+    iface = results[0]
+    harness.check(len(iface.members), 1, "Should have an operation")
+    operation = iface.members[0]
+    harness.check(len(operation.signatures()), 1, "Should have one signature")
+    (retval, args) = operation.signatures()[0]
+    harness.check(len(args), 1, "Should have an argument")
+    harness.check(
+        args[0].identifier.name,
+        "constructor",
+        "Should have an identifier named 'constructor'",
+    )
diff --git a/dom/bindings/parser/tests/test_argument_novoid.py b/dom/bindings/parser/tests/test_argument_novoid.py
new file mode 100644
index 0000000000..a72865e35b
--- /dev/null
+++ b/dom/bindings/parser/tests/test_argument_novoid.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface VoidArgument1 {
+              void foo(void arg2);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_arraybuffer.py b/dom/bindings/parser/tests/test_arraybuffer.py
new file mode 100644
index 0000000000..b762d06ac2
--- /dev/null
+++ b/dom/bindings/parser/tests/test_arraybuffer.py
@@ -0,0 +1,95 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestArrayBuffer {
+          attribute ArrayBuffer bufferAttr;
+          undefined bufferMethod(ArrayBuffer arg1, ArrayBuffer? arg2, sequence<ArrayBuffer> arg3);
+
+          attribute ArrayBufferView viewAttr;
+          undefined viewMethod(ArrayBufferView arg1, ArrayBufferView? arg2, sequence<ArrayBufferView> arg3);
+
+          attribute Int8Array int8ArrayAttr;
+          undefined int8ArrayMethod(Int8Array arg1, Int8Array? arg2, sequence<Int8Array> arg3);
+
+          attribute Uint8Array uint8ArrayAttr;
+          undefined uint8ArrayMethod(Uint8Array arg1, Uint8Array? arg2, sequence<Uint8Array> arg3);
+
+          attribute Uint8ClampedArray uint8ClampedArrayAttr;
+          undefined uint8ClampedArrayMethod(Uint8ClampedArray arg1, Uint8ClampedArray? arg2, sequence<Uint8ClampedArray> arg3);
+
+          attribute Int16Array int16ArrayAttr;
+          undefined int16ArrayMethod(Int16Array arg1, Int16Array? arg2, sequence<Int16Array> arg3);
+
+          attribute Uint16Array uint16ArrayAttr;
+          undefined uint16ArrayMethod(Uint16Array arg1, Uint16Array? arg2, sequence<Uint16Array> arg3);
+
+          attribute Int32Array int32ArrayAttr;
+          undefined int32ArrayMethod(Int32Array arg1, Int32Array? arg2, sequence<Int32Array> arg3);
+
+          attribute Uint32Array uint32ArrayAttr;
+          undefined uint32ArrayMethod(Uint32Array arg1, Uint32Array? arg2, sequence<Uint32Array> arg3);
+
+          attribute Float32Array float32ArrayAttr;
+          undefined float32ArrayMethod(Float32Array arg1, Float32Array? arg2, sequence<Float32Array> arg3);
+
+          attribute Float64Array float64ArrayAttr;
+          undefined float64ArrayMethod(Float64Array arg1, Float64Array? arg2, sequence<Float64Array> arg3);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    iface = results[0]
+
+    harness.ok(True, "TestArrayBuffer interface parsed without error")
+    harness.check(len(iface.members), 22, "Interface should have twenty two members")
+
+    members = iface.members
+
+    def checkStuff(attr, method, t):
+        harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Expect an IDLAttribute")
+        harness.ok(isinstance(method, WebIDL.IDLMethod), "Expect an IDLMethod")
+
+        harness.check(str(attr.type), t, "Expect an ArrayBuffer type")
+        harness.ok(attr.type.isSpiderMonkeyInterface(), "Should test as a js interface")
+
+        (retType, arguments) = method.signatures()[0]
+        harness.ok(retType.isUndefined(), "Should have an undefined return type")
+        harness.check(len(arguments), 3, "Expect 3 arguments")
+
+        harness.check(str(arguments[0].type), t, "Expect an ArrayBuffer type")
+        harness.ok(
+            arguments[0].type.isSpiderMonkeyInterface(), "Should test as a js interface"
+        )
+
+        harness.check(
+            str(arguments[1].type), t + "OrNull", "Expect an ArrayBuffer type"
+        )
+        harness.ok(
+            arguments[1].type.inner.isSpiderMonkeyInterface(),
+            "Should test as a js interface",
+        )
+
+        harness.check(
+            str(arguments[2].type), t + "Sequence", "Expect an ArrayBuffer type"
+        )
+        harness.ok(
+            arguments[2].type.inner.isSpiderMonkeyInterface(),
+            "Should test as a js interface",
+        )
+
+    checkStuff(members[0], members[1], "ArrayBuffer")
+    checkStuff(members[2], members[3], "ArrayBufferView")
+    checkStuff(members[4], members[5], "Int8Array")
+    checkStuff(members[6], members[7], "Uint8Array")
+    checkStuff(members[8], members[9], "Uint8ClampedArray")
+    checkStuff(members[10], members[11], "Int16Array")
+    checkStuff(members[12], members[13], "Uint16Array")
+    checkStuff(members[14], members[15], "Int32Array")
+    checkStuff(members[16], members[17], "Uint32Array")
+    checkStuff(members[18], members[19], "Float32Array")
+    checkStuff(members[20], members[21], "Float64Array")
diff --git a/dom/bindings/parser/tests/test_attr.py b/dom/bindings/parser/tests/test_attr.py
new file mode 100644
index 0000000000..b8dbccf41e
--- /dev/null
+++ b/dom/bindings/parser/tests/test_attr.py
@@ -0,0 +1,199 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    testData = [
+        ("::TestAttr%s::b", "b", "Byte%s", False),
+        ("::TestAttr%s::rb", "rb", "Byte%s", True),
+        ("::TestAttr%s::o", "o", "Octet%s", False),
+        ("::TestAttr%s::ro", "ro", "Octet%s", True),
+        ("::TestAttr%s::s", "s", "Short%s", False),
+        ("::TestAttr%s::rs", "rs", "Short%s", True),
+        ("::TestAttr%s::us", "us", "UnsignedShort%s", False),
+        ("::TestAttr%s::rus", "rus", "UnsignedShort%s", True),
+        ("::TestAttr%s::l", "l", "Long%s", False),
+        ("::TestAttr%s::rl", "rl", "Long%s", True),
+        ("::TestAttr%s::ul", "ul", "UnsignedLong%s", False),
+        ("::TestAttr%s::rul", "rul", "UnsignedLong%s", True),
+        ("::TestAttr%s::ll", "ll", "LongLong%s", False),
+        ("::TestAttr%s::rll", "rll", "LongLong%s", True),
+        ("::TestAttr%s::ull", "ull", "UnsignedLongLong%s", False),
+        ("::TestAttr%s::rull", "rull", "UnsignedLongLong%s", True),
+        ("::TestAttr%s::str", "str", "String%s", False),
+        ("::TestAttr%s::rstr", "rstr", "String%s", True),
+        ("::TestAttr%s::obj", "obj", "Object%s", False),
+        ("::TestAttr%s::robj", "robj", "Object%s", True),
+        ("::TestAttr%s::object", "object", "Object%s", False),
+        ("::TestAttr%s::f", "f", "Float%s", False),
+        ("::TestAttr%s::rf", "rf", "Float%s", True),
+    ]
+
+    parser.parse(
+        """
+        interface TestAttr {
+          attribute byte b;
+          readonly attribute byte rb;
+          attribute octet o;
+          readonly attribute octet ro;
+          attribute short s;
+          readonly attribute short rs;
+          attribute unsigned short us;
+          readonly attribute unsigned short rus;
+          attribute long l;
+          readonly attribute long rl;
+          attribute unsigned long ul;
+          readonly attribute unsigned long rul;
+          attribute long long ll;
+          readonly attribute long long rll;
+          attribute unsigned long long ull;
+          readonly attribute unsigned long long rull;
+          attribute DOMString str;
+          readonly attribute DOMString rstr;
+          attribute object obj;
+          readonly attribute object robj;
+          attribute object _object;
+          attribute float f;
+          readonly attribute float rf;
+        };
+
+        interface TestAttrNullable {
+          attribute byte? b;
+          readonly attribute byte? rb;
+          attribute octet? o;
+          readonly attribute octet? ro;
+          attribute short? s;
+          readonly attribute short? rs;
+          attribute unsigned short? us;
+          readonly attribute unsigned short? rus;
+          attribute long? l;
+          readonly attribute long? rl;
+          attribute unsigned long? ul;
+          readonly attribute unsigned long? rul;
+          attribute long long? ll;
+          readonly attribute long long? rll;
+          attribute unsigned long long? ull;
+          readonly attribute unsigned long long? rull;
+          attribute DOMString? str;
+          readonly attribute DOMString? rstr;
+          attribute object? obj;
+          readonly attribute object? robj;
+          attribute object? _object;
+          attribute float? f;
+          readonly attribute float? rf;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    def checkAttr(attr, QName, name, type, readonly):
+        harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+        harness.ok(attr.isAttr(), "Attr is an Attr")
+        harness.ok(not attr.isMethod(), "Attr is not an method")
+        harness.ok(not attr.isConst(), "Attr is not a const")
+        harness.check(attr.identifier.QName(), QName, "Attr has the right QName")
+        harness.check(attr.identifier.name, name, "Attr has the right name")
+        harness.check(str(attr.type), type, "Attr has the right type")
+        harness.check(attr.readonly, readonly, "Attr's readonly state is correct")
+
+    harness.ok(True, "TestAttr interface parsed without error.")
+    harness.check(len(results), 2, "Should be two productions.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestAttr", "Interface has the right QName"
+    )
+    harness.check(iface.identifier.name, "TestAttr", "Interface has the right name")
+    harness.check(
+        len(iface.members), len(testData), "Expect %s members" % len(testData)
+    )
+
+    attrs = iface.members
+
+    for i in range(len(attrs)):
+        data = testData[i]
+        attr = attrs[i]
+        (QName, name, type, readonly) = data
+        checkAttr(attr, QName % "", name, type % "", readonly)
+
+    iface = results[1]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestAttrNullable", "Interface has the right QName"
+    )
+    harness.check(
+        iface.identifier.name, "TestAttrNullable", "Interface has the right name"
+    )
+    harness.check(
+        len(iface.members), len(testData), "Expect %s members" % len(testData)
+    )
+
+    attrs = iface.members
+
+    for i in range(len(attrs)):
+        data = testData[i]
+        attr = attrs[i]
+        (QName, name, type, readonly) = data
+        checkAttr(attr, QName % "Nullable", name, type % "OrNull", readonly)
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [SetterThrows] readonly attribute boolean foo;
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [SetterThrows] on readonly attributes")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throw] readonly attribute boolean foo;
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should spell [Throws] correctly")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [SameObject] readonly attribute boolean foo;
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow [SameObject] on attributes not of interface type"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [SameObject] readonly attribute A foo;
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow [SameObject] on attributes of interface type")
diff --git a/dom/bindings/parser/tests/test_attr_sequence_type.py b/dom/bindings/parser/tests/test_attr_sequence_type.py
new file mode 100644
index 0000000000..7a23265daf
--- /dev/null
+++ b/dom/bindings/parser/tests/test_attr_sequence_type.py
@@ -0,0 +1,80 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface AttrSequenceType {
+              attribute sequence<object> foo;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Attribute type must not be a sequence type")
+
+    parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface AttrUnionWithSequenceType {
+              attribute (sequence<object> or DOMString) foo;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Attribute type must not be a union with a sequence member type")
+
+    parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface AttrNullableUnionWithSequenceType {
+              attribute (sequence<object>? or DOMString) foo;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Attribute type must not be a union with a nullable sequence " "member type",
+    )
+
+    parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            "\n"
+            "    interface AttrUnionWithUnionWithSequenceType {\n"
+            "      attribute ((sequence<object> or DOMString) or "
+            "AttrUnionWithUnionWithSequenceType) foo;\n"
+            "    };\n"
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Attribute type must not be a union type with a union member "
+        "type that has a sequence member type",
+    )
diff --git a/dom/bindings/parser/tests/test_attributes_on_types.py b/dom/bindings/parser/tests/test_attributes_on_types.py
new file mode 100644
index 0000000000..d47fc87110
--- /dev/null
+++ b/dom/bindings/parser/tests/test_attributes_on_types.py
@@ -0,0 +1,570 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    # Basic functionality
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [EnforceRange] long Foo;
+            typedef [Clamp] long Bar;
+            typedef [LegacyNullToEmptyString] DOMString Baz;
+            dictionary A {
+                required [EnforceRange] long a;
+                required [Clamp] long b;
+                [ChromeOnly, EnforceRange] long c;
+                Foo d;
+            };
+            interface B {
+                attribute Foo typedefFoo;
+                attribute [EnforceRange] long foo;
+                attribute [Clamp] long bar;
+                attribute [LegacyNullToEmptyString] DOMString baz;
+                undefined method([EnforceRange] long foo, [Clamp] long bar,
+                                 [LegacyNullToEmptyString] DOMString baz);
+                undefined method2(optional [EnforceRange] long foo, optional [Clamp] long bar,
+                                  optional [LegacyNullToEmptyString] DOMString baz);
+                undefined method3(optional [LegacyNullToEmptyString] UTF8String foo = "");
+            };
+            interface C {
+                attribute [EnforceRange] long? foo;
+                attribute [Clamp] long? bar;
+                undefined method([EnforceRange] long? foo, [Clamp] long? bar);
+                undefined method2(optional [EnforceRange] long? foo, optional [Clamp] long? bar);
+            };
+            interface Setlike {
+                setlike<[Clamp] long>;
+            };
+            interface Maplike {
+                maplike<[Clamp] long, [EnforceRange] long>;
+            };
+            interface Iterable {
+                iterable<[Clamp] long, [EnforceRange] long>;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(not threw, "Should not have thrown on parsing normal")
+    if not threw:
+        harness.check(
+            results[0].innerType.hasEnforceRange(), True, "Foo is [EnforceRange]"
+        )
+        harness.check(results[1].innerType.hasClamp(), True, "Bar is [Clamp]")
+        harness.check(
+            results[2].innerType.legacyNullToEmptyString,
+            True,
+            "Baz is [LegacyNullToEmptyString]",
+        )
+        A = results[3]
+        harness.check(
+            A.members[0].type.hasEnforceRange(), True, "A.a is [EnforceRange]"
+        )
+        harness.check(A.members[1].type.hasClamp(), True, "A.b is [Clamp]")
+        harness.check(
+            A.members[2].type.hasEnforceRange(), True, "A.c is [EnforceRange]"
+        )
+        harness.check(
+            A.members[3].type.hasEnforceRange(), True, "A.d is [EnforceRange]"
+        )
+        B = results[4]
+        harness.check(
+            B.members[0].type.hasEnforceRange(), True, "B.typedefFoo is [EnforceRange]"
+        )
+        harness.check(
+            B.members[1].type.hasEnforceRange(), True, "B.foo is [EnforceRange]"
+        )
+        harness.check(B.members[2].type.hasClamp(), True, "B.bar is [Clamp]")
+        harness.check(
+            B.members[3].type.legacyNullToEmptyString,
+            True,
+            "B.baz is [LegacyNullToEmptyString]",
+        )
+        method = B.members[4].signatures()[0][1]
+        harness.check(
+            method[0].type.hasEnforceRange(),
+            True,
+            "foo argument of method is [EnforceRange]",
+        )
+        harness.check(
+            method[1].type.hasClamp(), True, "bar argument of method is [Clamp]"
+        )
+        harness.check(
+            method[2].type.legacyNullToEmptyString,
+            True,
+            "baz argument of method is [LegacyNullToEmptyString]",
+        )
+        method2 = B.members[5].signatures()[0][1]
+        harness.check(
+            method2[0].type.hasEnforceRange(),
+            True,
+            "foo argument of method2 is [EnforceRange]",
+        )
+        harness.check(
+            method2[1].type.hasClamp(), True, "bar argument of method2 is [Clamp]"
+        )
+        harness.check(
+            method2[2].type.legacyNullToEmptyString,
+            True,
+            "baz argument of method2 is [LegacyNullToEmptyString]",
+        )
+
+        method3 = B.members[6].signatures()[0][1]
+        harness.check(
+            method3[0].type.legacyNullToEmptyString,
+            True,
+            "bar argument of method2 is [LegacyNullToEmptyString]",
+        )
+        harness.check(
+            method3[0].defaultValue.type.isUTF8String(),
+            True,
+            "default value of bar argument of method2 is correctly coerced to UTF8String",
+        )
+
+        C = results[5]
+        harness.ok(C.members[0].type.nullable(), "C.foo is nullable")
+        harness.ok(C.members[0].type.hasEnforceRange(), "C.foo has [EnforceRange]")
+        harness.ok(C.members[1].type.nullable(), "C.bar is nullable")
+        harness.ok(C.members[1].type.hasClamp(), "C.bar has [Clamp]")
+        method = C.members[2].signatures()[0][1]
+        harness.ok(method[0].type.nullable(), "foo argument of method is nullable")
+        harness.ok(
+            method[0].type.hasEnforceRange(),
+            "foo argument of method has [EnforceRange]",
+        )
+        harness.ok(method[1].type.nullable(), "bar argument of method is nullable")
+        harness.ok(method[1].type.hasClamp(), "bar argument of method has [Clamp]")
+        method2 = C.members[3].signatures()[0][1]
+        harness.ok(method2[0].type.nullable(), "foo argument of method2 is nullable")
+        harness.ok(
+            method2[0].type.hasEnforceRange(),
+            "foo argument of method2 has [EnforceRange]",
+        )
+        harness.ok(method2[1].type.nullable(), "bar argument of method2 is nullable")
+        harness.ok(method2[1].type.hasClamp(), "bar argument of method2 has [Clamp]")
+
+    # Test [AllowShared]
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [AllowShared] ArrayBufferView Foo;
+            dictionary A {
+                required [AllowShared] ArrayBufferView a;
+                [ChromeOnly, AllowShared] ArrayBufferView b;
+                Foo c;
+            };
+            interface B {
+                attribute Foo typedefFoo;
+                attribute [AllowShared] ArrayBufferView foo;
+                undefined method([AllowShared] ArrayBufferView foo);
+                undefined method2(optional [AllowShared] ArrayBufferView foo);
+            };
+            interface C {
+                attribute [AllowShared] ArrayBufferView? foo;
+                undefined method([AllowShared] ArrayBufferView? foo);
+                undefined method2(optional [AllowShared] ArrayBufferView? foo);
+            };
+            interface Setlike {
+                setlike<[AllowShared] ArrayBufferView>;
+            };
+            interface Maplike {
+                maplike<[Clamp] long, [AllowShared] ArrayBufferView>;
+            };
+            interface Iterable {
+                iterable<[Clamp] long, [AllowShared] ArrayBufferView>;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(not threw, "Should not have thrown on parsing normal")
+    if not threw:
+        harness.ok(results[0].innerType.hasAllowShared(), "Foo is [AllowShared]")
+        A = results[1]
+        harness.ok(A.members[0].type.hasAllowShared(), "A.a is [AllowShared]")
+        harness.ok(A.members[1].type.hasAllowShared(), "A.b is [AllowShared]")
+        harness.ok(A.members[2].type.hasAllowShared(), "A.c is [AllowShared]")
+        B = results[2]
+        harness.ok(B.members[0].type.hasAllowShared(), "B.typedefFoo is [AllowShared]")
+        harness.ok(B.members[1].type.hasAllowShared(), "B.foo is [AllowShared]")
+        method = B.members[2].signatures()[0][1]
+        harness.ok(
+            method[0].type.hasAllowShared(), "foo argument of method is [AllowShared]"
+        )
+        method2 = B.members[3].signatures()[0][1]
+        harness.ok(
+            method2[0].type.hasAllowShared(), "foo argument of method2 is [AllowShared]"
+        )
+        C = results[3]
+        harness.ok(C.members[0].type.nullable(), "C.foo is nullable")
+        harness.ok(C.members[0].type.hasAllowShared(), "C.foo is [AllowShared]")
+        method = C.members[1].signatures()[0][1]
+        harness.ok(method[0].type.nullable(), "foo argument of method is nullable")
+        harness.ok(
+            method[0].type.hasAllowShared(), "foo argument of method is [AllowShared]"
+        )
+        method2 = C.members[2].signatures()[0][1]
+        harness.ok(method2[0].type.nullable(), "foo argument of method2 is nullable")
+        harness.ok(
+            method2[0].type.hasAllowShared(), "foo argument of method2 is [AllowShared]"
+        )
+
+    ATTRIBUTES = [
+        ("[Clamp]", "long"),
+        ("[EnforceRange]", "long"),
+        ("[LegacyNullToEmptyString]", "DOMString"),
+        ("[AllowShared]", "ArrayBufferView"),
+    ]
+    TEMPLATES = [
+        (
+            "required dictionary members",
+            """
+            dictionary Foo {
+                %s required %s foo;
+            };
+        """,
+        ),
+        (
+            "optional arguments",
+            """
+            interface Foo {
+                undefined foo(%s optional %s foo);
+            };
+        """,
+        ),
+        (
+            "typedefs",
+            """
+            %s typedef %s foo;
+        """,
+        ),
+        (
+            "attributes",
+            """
+            interface Foo {
+            %s attribute %s foo;
+            };
+        """,
+        ),
+        (
+            "readonly attributes",
+            """
+            interface Foo {
+                readonly attribute %s %s foo;
+            };
+        """,
+        ),
+        (
+            "readonly unresolved attributes",
+            """
+            interface Foo {
+              readonly attribute Bar baz;
+            };
+            typedef %s %s Bar;
+        """,
+        ),
+        (
+            "method",
+            """
+            interface Foo {
+              %s %s foo();
+            };
+        """,
+        ),
+        (
+            "interface",
+            """
+            %s
+            interface Foo {
+              attribute %s foo;
+            };
+        """,
+        ),
+        (
+            "partial interface",
+            """
+            interface Foo {
+              undefined foo();
+            };
+            %s
+            partial interface Foo {
+              attribute %s bar;
+            };
+        """,
+        ),
+        (
+            "interface mixin",
+            """
+            %s
+            interface mixin Foo {
+              attribute %s foo;
+            };
+        """,
+        ),
+        (
+            "namespace",
+            """
+            %s
+            namespace Foo {
+              attribute %s foo;
+            };
+        """,
+        ),
+        (
+            "partial namespace",
+            """
+            namespace Foo {
+              undefined foo();
+            };
+            %s
+            partial namespace Foo {
+              attribute %s bar;
+            };
+        """,
+        ),
+        (
+            "dictionary",
+            """
+            %s
+            dictionary Foo {
+              %s foo;
+            };
+        """,
+        ),
+    ]
+
+    for name, template in TEMPLATES:
+        parser = parser.reset()
+        threw = False
+        try:
+            parser.parse(template % ("", "long"))
+            parser.finish()
+        except WebIDL.WebIDLError:
+            threw = True
+        harness.ok(not threw, "Template for %s parses without attributes" % name)
+        for attribute, type in ATTRIBUTES:
+            parser = parser.reset()
+            threw = False
+            try:
+                parser.parse(template % (attribute, type))
+                parser.finish()
+            except WebIDL.WebIDLError:
+                threw = True
+            harness.ok(threw, "Should not allow %s on %s" % (attribute, name))
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [Clamp, EnforceRange] long Foo;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow mixing [Clamp] and [EnforceRange]")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [EnforceRange, Clamp] long Foo;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow mixing [Clamp] and [EnforceRange]")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [Clamp] long Foo;
+            typedef [EnforceRange] Foo bar;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow mixing [Clamp] and [EnforceRange] via typedefs")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [EnforceRange] long Foo;
+            typedef [Clamp] Foo bar;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow mixing [Clamp] and [EnforceRange] via typedefs")
+
+    TYPES = [
+        "DOMString",
+        "unrestricted float",
+        "float",
+        "unrestricted double",
+        "double",
+    ]
+
+    for type in TYPES:
+        parser = parser.reset()
+        threw = False
+        try:
+            parser.parse(
+                """
+                typedef [Clamp] %s Foo;
+            """
+                % type
+            )
+            parser.finish()
+        except WebIDL.WebIDLError:
+            threw = True
+
+        harness.ok(threw, "Should not allow [Clamp] on %s" % type)
+
+        parser = parser.reset()
+        threw = False
+        try:
+            parser.parse(
+                """
+                typedef [EnforceRange] %s Foo;
+            """
+                % type
+            )
+            parser.finish()
+        except WebIDL.WebIDLError:
+            threw = True
+
+        harness.ok(threw, "Should not allow [EnforceRange] on %s" % type)
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [LegacyNullToEmptyString] long Foo;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow [LegacyNullToEmptyString] on long")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [LegacyNullToEmptyString] JSString Foo;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow [LegacyNullToEmptyString] on JSString")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [LegacyNullToEmptyString] DOMString? Foo;
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not allow [LegacyNullToEmptyString] on nullable DOMString"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [AllowShared] DOMString Foo;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[AllowShared] only allowed on buffer source types")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            typedef [AllowShared=something] ArrayBufferView Foo;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[AllowShared] must take no arguments")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+               undefined foo([Clamp] Bar arg);
+            };
+            typedef long Bar;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow type attributes on unresolved types")
+    harness.check(
+        results[0].members[0].signatures()[0][1][0].type.hasClamp(),
+        True,
+        "Unresolved types with type attributes should correctly resolve with attributes",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+               undefined foo(Bar arg);
+            };
+            typedef [Clamp] long Bar;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow type attributes on typedefs")
+    harness.check(
+        results[0].members[0].signatures()[0][1][0].type.hasClamp(),
+        True,
+        "Unresolved types that resolve to typedefs with attributes should correctly resolve with "
+        "attributes",
+    )
diff --git a/dom/bindings/parser/tests/test_builtin_filename.py b/dom/bindings/parser/tests/test_builtin_filename.py
new file mode 100644
index 0000000000..25ed32befc
--- /dev/null
+++ b/dom/bindings/parser/tests/test_builtin_filename.py
@@ -0,0 +1,11 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface Test {
+          attribute long b;
+        };
+    """
+    )
+
+    attr = parser.finish()[0].members[0]
+    harness.check(attr.type.filename(), "<builtin>", "Filename on builtin type")
diff --git a/dom/bindings/parser/tests/test_builtins.py b/dom/bindings/parser/tests/test_builtins.py
new file mode 100644
index 0000000000..a75a12e814
--- /dev/null
+++ b/dom/bindings/parser/tests/test_builtins.py
@@ -0,0 +1,59 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestBuiltins {
+          attribute boolean b;
+          attribute byte s8;
+          attribute octet u8;
+          attribute short s16;
+          attribute unsigned short u16;
+          attribute long s32;
+          attribute unsigned long u32;
+          attribute long long s64;
+          attribute unsigned long long u64;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestBuiltins interface parsed without error.")
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+    iface = results[0]
+    harness.check(
+        iface.identifier.QName(), "::TestBuiltins", "Interface has the right QName"
+    )
+    harness.check(iface.identifier.name, "TestBuiltins", "Interface has the right name")
+    harness.check(iface.parent, None, "Interface has no parent")
+
+    members = iface.members
+    harness.check(len(members), 9, "Should be one production")
+
+    names = ["b", "s8", "u8", "s16", "u16", "s32", "u32", "s64", "u64", "ts"]
+    types = [
+        "Boolean",
+        "Byte",
+        "Octet",
+        "Short",
+        "UnsignedShort",
+        "Long",
+        "UnsignedLong",
+        "LongLong",
+        "UnsignedLongLong",
+        "UnsignedLongLong",
+    ]
+    for i in range(9):
+        attr = members[i]
+        harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+        harness.check(
+            attr.identifier.QName(),
+            "::TestBuiltins::" + names[i],
+            "Attr has correct QName",
+        )
+        harness.check(attr.identifier.name, names[i], "Attr has correct name")
+        harness.check(str(attr.type), types[i], "Attr type is the correct name")
+        harness.ok(attr.type.isPrimitive(), "Should be a primitive type")
diff --git a/dom/bindings/parser/tests/test_bytestring.py b/dom/bindings/parser/tests/test_bytestring.py
new file mode 100644
index 0000000000..248d2716f3
--- /dev/null
+++ b/dom/bindings/parser/tests/test_bytestring.py
@@ -0,0 +1,125 @@
+# -*- coding: UTF-8 -*-
+
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestByteString {
+          attribute ByteString bs;
+          attribute DOMString ds;
+          };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestByteString interface parsed without error.")
+
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+    iface = results[0]
+    harness.check(
+        iface.identifier.QName(), "::TestByteString", "Interface has the right QName"
+    )
+    harness.check(
+        iface.identifier.name, "TestByteString", "Interface has the right name"
+    )
+    harness.check(iface.parent, None, "Interface has no parent")
+
+    members = iface.members
+    harness.check(len(members), 2, "Should be two productions")
+
+    attr = members[0]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    harness.check(
+        attr.identifier.QName(), "::TestByteString::bs", "Attr has correct QName"
+    )
+    harness.check(attr.identifier.name, "bs", "Attr has correct name")
+    harness.check(str(attr.type), "ByteString", "Attr type is the correct name")
+    harness.ok(attr.type.isByteString(), "Should be ByteString type")
+    harness.ok(attr.type.isString(), "Should be String collective type")
+    harness.ok(not attr.type.isDOMString(), "Should be not be DOMString type")
+
+    # now check we haven't broken DOMStrings in the process.
+    attr = members[1]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    harness.check(
+        attr.identifier.QName(), "::TestByteString::ds", "Attr has correct QName"
+    )
+    harness.check(attr.identifier.name, "ds", "Attr has correct name")
+    harness.check(str(attr.type), "String", "Attr type is the correct name")
+    harness.ok(attr.type.isDOMString(), "Should be DOMString type")
+    harness.ok(attr.type.isString(), "Should be String collective type")
+    harness.ok(not attr.type.isByteString(), "Should be not be ByteString type")
+
+    # Cannot represent constant ByteString in IDL.
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface ConstByteString {
+              const ByteString foo = "hello"
+              };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should have thrown a WebIDL error for ByteString default in interface"
+    )
+
+    # Can have optional ByteStrings with default values
+    try:
+        parser.parse(
+            """
+            interface OptionalByteString {
+              undefined passByteString(optional ByteString arg = "hello");
+              };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError as e:
+        harness.ok(
+            False,
+            "Should not have thrown a WebIDL error for ByteString "
+            "default in dictionary. " + str(e),
+        )
+
+    # Can have a default ByteString value in a dictionary
+    try:
+        parser.parse(
+            """
+        dictionary OptionalByteStringDict {
+          ByteString item = "some string";
+        };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError as e:
+        harness.ok(
+            False,
+            "Should not have thrown a WebIDL error for ByteString "
+            "default in dictionary. " + str(e),
+        )
+
+    # Don't allow control characters in ByteString literals
+    threw = False
+    try:
+        parser.parse(
+            """
+        dictionary OptionalByteStringDict2 {
+          ByteString item = "\x03";
+        };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown a WebIDL error for invalid ByteString "
+        "default in dictionary",
+    )
diff --git a/dom/bindings/parser/tests/test_callback.py b/dom/bindings/parser/tests/test_callback.py
new file mode 100644
index 0000000000..407644a6a8
--- /dev/null
+++ b/dom/bindings/parser/tests/test_callback.py
@@ -0,0 +1,42 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestCallback {
+          attribute CallbackType? listener;
+        };
+
+        callback CallbackType = boolean (unsigned long arg);
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestCallback interface parsed without error.")
+    harness.check(len(results), 2, "Should be two productions.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestCallback", "Interface has the right QName"
+    )
+    harness.check(iface.identifier.name, "TestCallback", "Interface has the right name")
+    harness.check(len(iface.members), 1, "Expect %s members" % 1)
+
+    attr = iface.members[0]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    harness.ok(attr.isAttr(), "Should be an attribute")
+    harness.ok(not attr.isMethod(), "Attr is not an method")
+    harness.ok(not attr.isConst(), "Attr is not a const")
+    harness.check(
+        attr.identifier.QName(), "::TestCallback::listener", "Attr has the right QName"
+    )
+    harness.check(attr.identifier.name, "listener", "Attr has the right name")
+    t = attr.type
+    harness.ok(not isinstance(t, WebIDL.IDLWrapperType), "Attr has the right type")
+    harness.ok(isinstance(t, WebIDL.IDLNullableType), "Attr has the right type")
+    harness.ok(t.isCallback(), "Attr has the right type")
+
+    callback = results[1]
+    harness.ok(not callback.isConstructor(), "callback is not constructor")
diff --git a/dom/bindings/parser/tests/test_callback_constructor.py b/dom/bindings/parser/tests/test_callback_constructor.py
new file mode 100644
index 0000000000..67ea8ff755
--- /dev/null
+++ b/dom/bindings/parser/tests/test_callback_constructor.py
@@ -0,0 +1,84 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestCallbackConstructor {
+          attribute CallbackConstructorType? constructorAttribute;
+        };
+
+        callback constructor CallbackConstructorType = TestCallbackConstructor (unsigned long arg);
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestCallbackConstructor interface parsed without error.")
+    harness.check(len(results), 2, "Should be two productions.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(),
+        "::TestCallbackConstructor",
+        "Interface has the right QName",
+    )
+    harness.check(
+        iface.identifier.name, "TestCallbackConstructor", "Interface has the right name"
+    )
+    harness.check(len(iface.members), 1, "Expect %s members" % 1)
+
+    attr = iface.members[0]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    harness.ok(attr.isAttr(), "Should be an attribute")
+    harness.ok(not attr.isMethod(), "Attr is not an method")
+    harness.ok(not attr.isConst(), "Attr is not a const")
+    harness.check(
+        attr.identifier.QName(),
+        "::TestCallbackConstructor::constructorAttribute",
+        "Attr has the right QName",
+    )
+    harness.check(
+        attr.identifier.name, "constructorAttribute", "Attr has the right name"
+    )
+    t = attr.type
+    harness.ok(not isinstance(t, WebIDL.IDLWrapperType), "Attr has the right type")
+    harness.ok(isinstance(t, WebIDL.IDLNullableType), "Attr has the right type")
+    harness.ok(t.isCallback(), "Attr has the right type")
+
+    callback = results[1]
+    harness.ok(callback.isConstructor(), "Callback is constructor")
+
+    parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyTreatNonObjectAsNull]
+            callback constructor CallbackConstructorType = object ();
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should throw on LegacyTreatNonObjectAsNull callback constructors"
+    )
+
+    parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [MOZ_CAN_RUN_SCRIPT_BOUNDARY]
+            callback constructor CallbackConstructorType = object ();
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not permit MOZ_CAN_RUN_SCRIPT_BOUNDARY callback constructors"
+    )
diff --git a/dom/bindings/parser/tests/test_callback_interface.py b/dom/bindings/parser/tests/test_callback_interface.py
new file mode 100644
index 0000000000..102e96401b
--- /dev/null
+++ b/dom/bindings/parser/tests/test_callback_interface.py
@@ -0,0 +1,106 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        callback interface TestCallbackInterface {
+          attribute boolean bool;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    iface = results[0]
+
+    harness.ok(iface.isCallback(), "Interface should be a callback")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestInterface {
+            };
+            callback interface TestCallbackInterface : TestInterface {
+              attribute boolean bool;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow non-callback parent of callback interface")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestInterface : TestCallbackInterface {
+            };
+            callback interface TestCallbackInterface {
+              attribute boolean bool;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow callback parent of non-callback interface")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        callback interface TestCallbackInterface1 {
+          undefined foo();
+        };
+        callback interface TestCallbackInterface2 {
+          undefined foo(DOMString arg);
+          undefined foo(TestCallbackInterface1 arg);
+        };
+        callback interface TestCallbackInterface3 {
+          undefined foo(DOMString arg);
+          undefined foo(TestCallbackInterface1 arg);
+          static undefined bar();
+        };
+        callback interface TestCallbackInterface4 {
+          undefined foo(DOMString arg);
+          undefined foo(TestCallbackInterface1 arg);
+          static undefined bar();
+          const long baz = 5;
+        };
+        callback interface TestCallbackInterface5 {
+          static attribute boolean bool;
+          undefined foo();
+        };
+        callback interface TestCallbackInterface6 {
+          undefined foo(DOMString arg);
+          undefined foo(TestCallbackInterface1 arg);
+          undefined bar();
+        };
+        callback interface TestCallbackInterface7 {
+          static attribute boolean bool;
+        };
+        callback interface TestCallbackInterface8 {
+          attribute boolean bool;
+        };
+        callback interface TestCallbackInterface9 : TestCallbackInterface1 {
+          undefined foo();
+        };
+        callback interface TestCallbackInterface10 : TestCallbackInterface1 {
+          undefined bar();
+        };
+    """
+    )
+    results = parser.finish()
+    for i, iface in enumerate(results):
+        harness.check(
+            iface.isSingleOperationInterface(),
+            i < 4,
+            "Interface %s should be a single operation interface"
+            % iface.identifier.name,
+        )
diff --git a/dom/bindings/parser/tests/test_cereactions.py b/dom/bindings/parser/tests/test_cereactions.py
new file mode 100644
index 0000000000..2aa4da40c8
--- /dev/null
+++ b/dom/bindings/parser/tests/test_cereactions.py
@@ -0,0 +1,160 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              [CEReactions(DOMString a)] undefined foo(boolean arg2);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] with an argument")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              [CEReactions(DOMString b)] readonly attribute boolean bar;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] with an argument")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              [CEReactions] attribute boolean bar;
+            };
+        """
+        )
+
+        parser.finish()
+    except Exception as e:
+        harness.ok(
+            False,
+            "Shouldn't have thrown for [CEReactions] used on writable attribute. %s"
+            % e,
+        )
+        threw = True
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              [CEReactions] undefined foo(boolean arg2);
+            };
+        """
+        )
+
+        parser.finish()
+    except Exception as e:
+        harness.ok(
+            False,
+            "Shouldn't have thrown for [CEReactions] used on regular operations. %s"
+            % e,
+        )
+        threw = True
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              [CEReactions] readonly attribute boolean A;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should have thrown for [CEReactions] used on a readonly attribute"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [CEReactions]
+            interface Foo {
+            }
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] used on a interface")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Foo {
+            [CEReactions] getter any(DOMString name);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] used on a named getter")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Foo {
+            [CEReactions] legacycaller double compute(double x);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] used on a legacycaller")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Foo {
+            [CEReactions] stringifier DOMString ();
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for [CEReactions] used on a stringifier")
diff --git a/dom/bindings/parser/tests/test_conditional_dictionary_member.py b/dom/bindings/parser/tests/test_conditional_dictionary_member.py
new file mode 100644
index 0000000000..2aef8ebe8f
--- /dev/null
+++ b/dom/bindings/parser/tests/test_conditional_dictionary_member.py
@@ -0,0 +1,128 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      dictionary Dict {
+        any foo;
+        [ChromeOnly] any bar;
+      };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should have a dictionary")
+    members = results[0].members
+    harness.check(len(members), 2, "Should have two members")
+    # Note that members are ordered lexicographically, so "bar" comes
+    # before "foo".
+    harness.ok(
+        members[0].getExtendedAttribute("ChromeOnly"), "First member is not ChromeOnly"
+    )
+    harness.ok(
+        not members[1].getExtendedAttribute("ChromeOnly"), "Second member is ChromeOnly"
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      dictionary Dict {
+        any foo;
+        any bar;
+      };
+
+      interface Iface {
+        [Constant, Cached] readonly attribute Dict dict;
+      };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 2, "Should have a dictionary and an interface")
+
+    parser = parser.reset()
+    exception = None
+    try:
+        parser.parse(
+            """
+        dictionary Dict {
+          any foo;
+          [ChromeOnly] any bar;
+        };
+
+        interface Iface {
+          [Constant, Cached] readonly attribute Dict dict;
+        };
+      """
+        )
+        results = parser.finish()
+    except Exception as e:
+        exception = e
+
+    harness.ok(exception, "Should have thrown.")
+    harness.check(
+        exception.message,
+        "[Cached] and [StoreInSlot] must not be used on an attribute "
+        "whose type contains a [ChromeOnly] dictionary member",
+        "Should have thrown the right exception",
+    )
+
+    parser = parser.reset()
+    exception = None
+    try:
+        parser.parse(
+            """
+        dictionary ParentDict {
+          [ChromeOnly] any bar;
+        };
+
+        dictionary Dict : ParentDict {
+          any foo;
+        };
+
+        interface Iface {
+          [Constant, Cached] readonly attribute Dict dict;
+        };
+      """
+        )
+        results = parser.finish()
+    except Exception as e:
+        exception = e
+
+    harness.ok(exception, "Should have thrown (2).")
+    harness.check(
+        exception.message,
+        "[Cached] and [StoreInSlot] must not be used on an attribute "
+        "whose type contains a [ChromeOnly] dictionary member",
+        "Should have thrown the right exception (2)",
+    )
+
+    parser = parser.reset()
+    exception = None
+    try:
+        parser.parse(
+            """
+        dictionary GrandParentDict {
+          [ChromeOnly] any baz;
+        };
+
+        dictionary ParentDict : GrandParentDict {
+          any bar;
+        };
+
+        dictionary Dict : ParentDict {
+          any foo;
+        };
+
+        interface Iface {
+          [Constant, Cached] readonly attribute Dict dict;
+        };
+      """
+        )
+        results = parser.finish()
+    except Exception as e:
+        exception = e
+
+    harness.ok(exception, "Should have thrown (3).")
+    harness.check(
+        exception.message,
+        "[Cached] and [StoreInSlot] must not be used on an attribute "
+        "whose type contains a [ChromeOnly] dictionary member",
+        "Should have thrown the right exception (3)",
+    )
diff --git a/dom/bindings/parser/tests/test_const.py b/dom/bindings/parser/tests/test_const.py
new file mode 100644
index 0000000000..da83db41ef
--- /dev/null
+++ b/dom/bindings/parser/tests/test_const.py
@@ -0,0 +1,96 @@
+import WebIDL
+
+expected = [
+    ("::TestConsts::zero", "zero", "Byte", 0),
+    ("::TestConsts::b", "b", "Byte", -1),
+    ("::TestConsts::o", "o", "Octet", 2),
+    ("::TestConsts::s", "s", "Short", -3),
+    ("::TestConsts::us", "us", "UnsignedShort", 4),
+    ("::TestConsts::l", "l", "Long", -5),
+    ("::TestConsts::ul", "ul", "UnsignedLong", 6),
+    ("::TestConsts::ull", "ull", "UnsignedLongLong", 7),
+    ("::TestConsts::ll", "ll", "LongLong", -8),
+    ("::TestConsts::t", "t", "Boolean", True),
+    ("::TestConsts::f", "f", "Boolean", False),
+    ("::TestConsts::fl", "fl", "Float", 0.2),
+    ("::TestConsts::db", "db", "Double", 0.2),
+    ("::TestConsts::ufl", "ufl", "UnrestrictedFloat", 0.2),
+    ("::TestConsts::udb", "udb", "UnrestrictedDouble", 0.2),
+    ("::TestConsts::fli", "fli", "Float", 2),
+    ("::TestConsts::dbi", "dbi", "Double", 2),
+    ("::TestConsts::ufli", "ufli", "UnrestrictedFloat", 2),
+    ("::TestConsts::udbi", "udbi", "UnrestrictedDouble", 2),
+]
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestConsts {
+          const byte zero = 0;
+          const byte b = -1;
+          const octet o = 2;
+          const short s = -3;
+          const unsigned short us = 0x4;
+          const long l = -0X5;
+          const unsigned long ul = 6;
+          const unsigned long long ull = 7;
+          const long long ll = -010;
+          const boolean t = true;
+          const boolean f = false;
+          const float fl = 0.2;
+          const double db = 0.2;
+          const unrestricted float ufl = 0.2;
+          const unrestricted double udb = 0.2;
+          const float fli = 2;
+          const double dbi = 2;
+          const unrestricted float ufli = 2;
+          const unrestricted double udbi = 2;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestConsts interface parsed without error.")
+    harness.check(len(results), 1, "Should be one production.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestConsts", "Interface has the right QName"
+    )
+    harness.check(iface.identifier.name, "TestConsts", "Interface has the right name")
+    harness.check(
+        len(iface.members), len(expected), "Expect %s members" % len(expected)
+    )
+
+    for const, (QName, name, type, value) in zip(iface.members, expected):
+        harness.ok(isinstance(const, WebIDL.IDLConst), "Should be an IDLConst")
+        harness.ok(const.isConst(), "Const is a const")
+        harness.ok(not const.isAttr(), "Const is not an attr")
+        harness.ok(not const.isMethod(), "Const is not a method")
+        harness.check(const.identifier.QName(), QName, "Const has the right QName")
+        harness.check(const.identifier.name, name, "Const has the right name")
+        harness.check(str(const.type), type, "Const has the right type")
+        harness.ok(const.type.isPrimitive(), "All consts should be primitive")
+        harness.check(
+            str(const.value.type),
+            str(const.type),
+            "Const's value has the same type as the type",
+        )
+        harness.check(const.value.value, value, "Const value has the right value.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface TestConsts {
+            const boolean? zero = 0;
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Nullable types are not allowed for consts.")
diff --git a/dom/bindings/parser/tests/test_constructor.py b/dom/bindings/parser/tests/test_constructor.py
new file mode 100644
index 0000000000..1a08a828fd
--- /dev/null
+++ b/dom/bindings/parser/tests/test_constructor.py
@@ -0,0 +1,596 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    def checkArgument(argument, QName, name, type, optional, variadic):
+        harness.ok(isinstance(argument, WebIDL.IDLArgument), "Should be an IDLArgument")
+        harness.check(
+            argument.identifier.QName(), QName, "Argument has the right QName"
+        )
+        harness.check(argument.identifier.name, name, "Argument has the right name")
+        harness.check(str(argument.type), type, "Argument has the right return type")
+        harness.check(
+            argument.optional, optional, "Argument has the right optional value"
+        )
+        harness.check(
+            argument.variadic, variadic, "Argument has the right variadic value"
+        )
+
+    def checkMethod(
+        method,
+        QName,
+        name,
+        signatures,
+        static=True,
+        getter=False,
+        setter=False,
+        deleter=False,
+        legacycaller=False,
+        stringifier=False,
+        chromeOnly=False,
+        htmlConstructor=False,
+        secureContext=False,
+        pref=None,
+        func=None,
+    ):
+        harness.ok(isinstance(method, WebIDL.IDLMethod), "Should be an IDLMethod")
+        harness.ok(method.isMethod(), "Method is a method")
+        harness.ok(not method.isAttr(), "Method is not an attr")
+        harness.ok(not method.isConst(), "Method is not a const")
+        harness.check(method.identifier.QName(), QName, "Method has the right QName")
+        harness.check(method.identifier.name, name, "Method has the right name")
+        harness.check(method.isStatic(), static, "Method has the correct static value")
+        harness.check(method.isGetter(), getter, "Method has the correct getter value")
+        harness.check(method.isSetter(), setter, "Method has the correct setter value")
+        harness.check(
+            method.isDeleter(), deleter, "Method has the correct deleter value"
+        )
+        harness.check(
+            method.isLegacycaller(),
+            legacycaller,
+            "Method has the correct legacycaller value",
+        )
+        harness.check(
+            method.isStringifier(),
+            stringifier,
+            "Method has the correct stringifier value",
+        )
+        harness.check(
+            method.getExtendedAttribute("ChromeOnly") is not None,
+            chromeOnly,
+            "Method has the correct value for ChromeOnly",
+        )
+        harness.check(
+            method.isHTMLConstructor(),
+            htmlConstructor,
+            "Method has the correct htmlConstructor value",
+        )
+        harness.check(
+            len(method.signatures()),
+            len(signatures),
+            "Method has the correct number of signatures",
+        )
+        harness.check(
+            method.getExtendedAttribute("Pref"),
+            pref,
+            "Method has the correct pref value",
+        )
+        harness.check(
+            method.getExtendedAttribute("Func"),
+            func,
+            "Method has the correct func value",
+        )
+        harness.check(
+            method.getExtendedAttribute("SecureContext") is not None,
+            secureContext,
+            "Method has the correct SecureContext value",
+        )
+
+        sigpairs = zip(method.signatures(), signatures)
+        for gotSignature, expectedSignature in sigpairs:
+            (gotRetType, gotArgs) = gotSignature
+            (expectedRetType, expectedArgs) = expectedSignature
+
+            harness.check(
+                str(gotRetType), expectedRetType, "Method has the expected return type."
+            )
+
+            for i in range(0, len(gotArgs)):
+                (QName, name, type, optional, variadic) = expectedArgs[i]
+                checkArgument(gotArgs[i], QName, name, type, optional, variadic)
+
+    def checkResults(results):
+        harness.check(len(results), 3, "Should be three productions")
+        harness.ok(
+            isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface"
+        )
+        harness.ok(
+            isinstance(results[1], WebIDL.IDLInterface), "Should be an IDLInterface"
+        )
+        harness.ok(
+            isinstance(results[2], WebIDL.IDLInterface), "Should be an IDLInterface"
+        )
+
+        checkMethod(
+            results[0].ctor(),
+            "::TestConstructorNoArgs::constructor",
+            "constructor",
+            [("TestConstructorNoArgs (Wrapper)", [])],
+        )
+        harness.check(
+            len(results[0].members), 0, "TestConstructorNoArgs should not have members"
+        )
+        checkMethod(
+            results[1].ctor(),
+            "::TestConstructorWithArgs::constructor",
+            "constructor",
+            [
+                (
+                    "TestConstructorWithArgs (Wrapper)",
+                    [
+                        (
+                            "::TestConstructorWithArgs::constructor::name",
+                            "name",
+                            "String",
+                            False,
+                            False,
+                        )
+                    ],
+                )
+            ],
+        )
+        harness.check(
+            len(results[1].members),
+            0,
+            "TestConstructorWithArgs should not have members",
+        )
+        checkMethod(
+            results[2].ctor(),
+            "::TestConstructorOverloads::constructor",
+            "constructor",
+            [
+                (
+                    "TestConstructorOverloads (Wrapper)",
+                    [
+                        (
+                            "::TestConstructorOverloads::constructor::foo",
+                            "foo",
+                            "Object",
+                            False,
+                            False,
+                        )
+                    ],
+                ),
+                (
+                    "TestConstructorOverloads (Wrapper)",
+                    [
+                        (
+                            "::TestConstructorOverloads::constructor::bar",
+                            "bar",
+                            "Boolean",
+                            False,
+                            False,
+                        )
+                    ],
+                ),
+            ],
+        )
+        harness.check(
+            len(results[2].members),
+            0,
+            "TestConstructorOverloads should not have members",
+        )
+
+    parser.parse(
+        """
+        interface TestConstructorNoArgs {
+          constructor();
+        };
+
+        interface TestConstructorWithArgs {
+          constructor(DOMString name);
+        };
+
+        interface TestConstructorOverloads {
+          constructor(object foo);
+          constructor(boolean bar);
+        };
+    """
+    )
+    results = parser.finish()
+    checkResults(results)
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestPrefConstructor {
+            [Pref="dom.webidl.test1"] constructor();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestPrefConstructor::constructor",
+        "constructor",
+        [("TestPrefConstructor (Wrapper)", [])],
+        pref=["dom.webidl.test1"],
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestChromeOnlyConstructor {
+          [ChromeOnly] constructor();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestChromeOnlyConstructor::constructor",
+        "constructor",
+        [("TestChromeOnlyConstructor (Wrapper)", [])],
+        chromeOnly=True,
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestSCConstructor {
+            [SecureContext] constructor();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestSCConstructor::constructor",
+        "constructor",
+        [("TestSCConstructor (Wrapper)", [])],
+        secureContext=True,
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestFuncConstructor {
+            [Func="IsNotUAWidget"] constructor();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestFuncConstructor::constructor",
+        "constructor",
+        [("TestFuncConstructor (Wrapper)", [])],
+        func=["IsNotUAWidget"],
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        (
+            "\n"
+            "    interface TestPrefChromeOnlySCFuncConstructor {\n"
+            '        [ChromeOnly, Pref="dom.webidl.test1", SecureContext, '
+            'Func="IsNotUAWidget"]\n'
+            "        constructor();\n"
+            "    };\n"
+        )
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestPrefChromeOnlySCFuncConstructor::constructor",
+        "constructor",
+        [("TestPrefChromeOnlySCFuncConstructor (Wrapper)", [])],
+        func=["IsNotUAWidget"],
+        pref=["dom.webidl.test1"],
+        chromeOnly=True,
+        secureContext=True,
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestHTMLConstructor {
+          [HTMLConstructor] constructor();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    checkMethod(
+        results[0].ctor(),
+        "::TestHTMLConstructor::constructor",
+        "constructor",
+        [("TestHTMLConstructor (Wrapper)", [])],
+        htmlConstructor=True,
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+        interface TestChromeOnlyConstructor {
+          constructor()
+          [ChromeOnly] constructor(DOMString a);
+        };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have both a constructor and a ChromeOnly constructor")
+
+    # Test HTMLConstructor with argument
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorWithArgs {
+              [HTMLConstructor] constructor(DOMString a);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "HTMLConstructor should take no argument")
+
+    # Test HTMLConstructor on a callback interface
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            callback interface TestHTMLConstructorOnCallbackInterface {
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "HTMLConstructor can't be used on a callback interface")
+
+    # Test HTMLConstructor and constructor operation
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              constructor();
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have both a constructor and a HTMLConstructor")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [Throws]
+              constructor();
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have both a throwing constructor and a HTMLConstructor")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              constructor(DOMString a);
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have both a HTMLConstructor and a constructor operation")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [Throws]
+              constructor(DOMString a);
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Can't have both a HTMLConstructor and a throwing constructor " "operation",
+    )
+
+    # Test HTMLConstructor and [ChromeOnly] constructor operation
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [ChromeOnly]
+              constructor();
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have both a ChromeOnly constructor and a HTMLConstructor")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [Throws, ChromeOnly]
+              constructor();
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Can't have both a throwing chromeonly constructor and a " "HTMLConstructor",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [ChromeOnly]
+              constructor(DOMString a);
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Can't have both a HTMLConstructor and a chromeonly constructor " "operation",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestHTMLConstructorAndConstructor {
+              [Throws, ChromeOnly]
+              constructor(DOMString a);
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Can't have both a HTMLConstructor and a throwing chromeonly "
+        "constructor operation",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyNoInterfaceObject]
+            interface InterfaceWithoutInterfaceObject {
+              constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Can't have a constructor operation on a [LegacyNoInterfaceObject] "
+        "interface",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface InterfaceWithPartial {
+            };
+
+            partial interface InterfaceWithPartial {
+              constructor();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have a constructor operation on a partial interface")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface InterfaceWithMixin {
+            };
+
+            interface mixin Mixin {
+              constructor();
+            };
+
+            InterfaceWithMixin includes Mixin
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Can't have a constructor operation on a mixin")
diff --git a/dom/bindings/parser/tests/test_constructor_global.py b/dom/bindings/parser/tests/test_constructor_global.py
new file mode 100644
index 0000000000..5962b8745d
--- /dev/null
+++ b/dom/bindings/parser/tests/test_constructor_global.py
@@ -0,0 +1,72 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=TestConstructorGlobal]
+            interface TestConstructorGlobal {
+              constructor();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=TestLegacyFactoryFunctionGlobal,
+             LegacyFactoryFunction=FooBar]
+            interface TestLegacyFactoryFunctionGlobal {
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyFactoryFunction=FooBar, Global,
+             Exposed=TestLegacyFactoryFunctionGlobal]
+            interface TestLegacyFactoryFunctionGlobal {
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=TestHTMLConstructorGlobal]
+            interface TestHTMLConstructorGlobal {
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_constructor_no_interface_object.py b/dom/bindings/parser/tests/test_constructor_no_interface_object.py
new file mode 100644
index 0000000000..b8f8589f28
--- /dev/null
+++ b/dom/bindings/parser/tests/test_constructor_no_interface_object.py
@@ -0,0 +1,50 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyNoInterfaceObject]
+            interface TestConstructorLegacyNoInterfaceObject {
+              constructor();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+
+    parser.parse(
+        """
+        [LegacyNoInterfaceObject, LegacyFactoryFunction=FooBar]
+        interface TestLegacyFactoryFunctionLegacyNoInterfaceObject {
+        };
+    """
+    )
+
+    # Test HTMLConstructor and LegacyNoInterfaceObject
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyNoInterfaceObject]
+            interface TestHTMLConstructorLegacyNoInterfaceObject {
+              [HTMLConstructor] constructor();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_deduplicate.py b/dom/bindings/parser/tests/test_deduplicate.py
new file mode 100644
index 0000000000..2308f6201e
--- /dev/null
+++ b/dom/bindings/parser/tests/test_deduplicate.py
@@ -0,0 +1,17 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface Foo;
+        interface Bar;
+        interface Foo;
+        """
+    )
+
+    results = parser.finish()
+
+    # There should be no duplicate interfaces in the result.
+    expectedNames = sorted(["Foo", "Bar"])
+    actualNames = sorted(map(lambda iface: iface.identifier.name, results))
+    harness.check(
+        actualNames, expectedNames, "Parser shouldn't output duplicate names."
+    )
diff --git a/dom/bindings/parser/tests/test_dictionary.py b/dom/bindings/parser/tests/test_dictionary.py
new file mode 100644
index 0000000000..80c13a4238
--- /dev/null
+++ b/dom/bindings/parser/tests/test_dictionary.py
@@ -0,0 +1,878 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      dictionary Dict2 : Dict1 {
+        long child = 5;
+        Dict1 aaandAnother;
+      };
+      dictionary Dict1 {
+        long parent;
+        double otherParent;
+      };
+    """
+    )
+    results = parser.finish()
+
+    dict1 = results[1]
+    dict2 = results[0]
+
+    harness.check(len(dict1.members), 2, "Dict1 has two members")
+    harness.check(len(dict2.members), 2, "Dict2 has four members")
+
+    harness.check(
+        dict1.members[0].identifier.name, "otherParent", "'o' comes before 'p'"
+    )
+    harness.check(
+        dict1.members[1].identifier.name, "parent", "'o' really comes before 'p'"
+    )
+    harness.check(
+        dict2.members[0].identifier.name, "aaandAnother", "'a' comes before 'c'"
+    )
+    harness.check(
+        dict2.members[1].identifier.name, "child", "'a' really comes before 'c'"
+    )
+
+    # Test partial dictionary.
+    parser = parser.reset()
+    parser.parse(
+        """
+      dictionary A {
+        long c;
+        long g;
+      };
+      partial dictionary A {
+        long h;
+        long d;
+      };
+    """
+    )
+    results = parser.finish()
+
+    dict1 = results[0]
+    harness.check(len(dict1.members), 4, "Dict1 has four members")
+    harness.check(dict1.members[0].identifier.name, "c", "c should be first")
+    harness.check(dict1.members[1].identifier.name, "d", "d should come after c")
+    harness.check(dict1.members[2].identifier.name, "g", "g should come after d")
+    harness.check(dict1.members[3].identifier.name, "h", "h should be last")
+
+    # Now reset our parser
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          dictionary Dict {
+            long prop = 5;
+            long prop;
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow name duplication in a dictionary")
+
+    # Test no name duplication across normal and partial dictionary.
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          dictionary A {
+            long prop = 5;
+          };
+          partial dictionary A {
+            long prop;
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not allow name duplication across normal and partial dictionary"
+    )
+
+    # Now reset our parser again
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          dictionary Dict1 : Dict2 {
+            long prop = 5;
+          };
+          dictionary Dict2 : Dict3 {
+            long prop2;
+          };
+          dictionary Dict3 {
+            double prop;
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not allow name duplication in a dictionary and " "its ancestor"
+    )
+
+    # More reset
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Iface {};
+          dictionary Dict : Iface {
+            long prop;
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow non-dictionary parents for dictionaries")
+
+    # Even more reset
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A : B {};
+            dictionary B : A {};
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow cycles in dictionary inheritance chains")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+              [LegacyNullToEmptyString] DOMString foo;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not allow [LegacyNullToEmptyString] on dictionary members"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(A arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Trailing dictionary arg must be optional")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional A arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Trailing dictionary arg must have a default value")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo((A or DOMString) arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Trailing union arg containing a dictionary must be optional")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional (A or DOMString) arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Trailing union arg containing a dictionary must have a default value"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(A arg1, optional long arg2);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Dictionary arg followed by optional arg must be optional")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional A arg1, optional long arg2);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Dictionary arg followed by optional arg must have default value")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(A arg1, optional long arg2, long arg3);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        not threw,
+        "Dictionary arg followed by non-optional arg doesn't have to be optional",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo((A or DOMString) arg1, optional long arg2);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Union arg containing dictionary followed by optional arg must " "be optional",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional (A or DOMString) arg1, optional long arg2);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Union arg containing dictionary followed by optional arg must "
+        "have a default value",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(A arg1, long arg2);
+            };
+        """
+    )
+    parser.finish()
+    harness.ok(True, "Dictionary arg followed by required arg can be required")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional A? arg1 = {});
+            };
+        """
+        )
+        parser.finish()
+    except Exception as x:
+        threw = x
+
+    harness.ok(threw, "Optional dictionary arg must not be nullable")
+    harness.ok(
+        "nullable" in str(threw),
+        "Must have the expected exception for optional nullable dictionary arg",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+              required long x;
+            };
+            interface X {
+              undefined doFoo(A? arg1);
+            };
+        """
+        )
+        parser.finish()
+    except Exception as x:
+        threw = x
+
+    harness.ok(threw, "Required dictionary arg must not be nullable")
+    harness.ok(
+        "nullable" in str(threw),
+        "Must have the expected exception for required nullable " "dictionary arg",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional (A or long)? arg1 = {});
+            };
+        """
+        )
+        parser.finish()
+    except Exception as x:
+        threw = x
+
+    harness.ok(threw, "Dictionary arg must not be in an optional nullable union")
+    harness.ok(
+        "nullable" in str(threw),
+        "Must have the expected exception for optional nullable union "
+        "arg containing dictionary",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+              required long x;
+            };
+            interface X {
+              undefined doFoo((A or long)? arg1);
+            };
+        """
+        )
+        parser.finish()
+    except Exception as x:
+        threw = x
+
+    harness.ok(threw, "Dictionary arg must not be in a required nullable union")
+    harness.ok(
+        "nullable" in str(threw),
+        "Must have the expected exception for required nullable union "
+        "arg containing dictionary",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(sequence<A?> arg1);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(not threw, "Nullable union should be allowed in a sequence argument")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional (A or long?) arg1);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Dictionary must not be in a union with a nullable type")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+            };
+            interface X {
+              undefined doFoo(optional (long? or A) arg1);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "A nullable type must not be in a union with a dictionary")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary A {
+        };
+        interface X {
+          A? doFoo();
+        };
+    """
+    )
+    parser.finish()
+    harness.ok(True, "Dictionary return value can be nullable")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary A {
+        };
+        interface X {
+          undefined doFoo(optional A arg = {});
+        };
+    """
+    )
+    parser.finish()
+    harness.ok(True, "Dictionary arg should actually parse")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary A {
+        };
+        interface X {
+          undefined doFoo(optional (A or DOMString) arg = {});
+        };
+    """
+    )
+    parser.finish()
+    harness.ok(True, "Union arg containing a dictionary should actually parse")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary A {
+        };
+        interface X {
+          undefined doFoo(optional (A or DOMString) arg = "abc");
+        };
+    """
+    )
+    parser.finish()
+    harness.ok(
+        True,
+        "Union arg containing a dictionary with string default should actually parse",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              Foo foo;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Member type must not be its Dictionary.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo3 : Foo {
+              short d;
+            };
+
+            dictionary Foo2 : Foo3 {
+              boolean c;
+            };
+
+            dictionary Foo1 : Foo2 {
+              long a;
+            };
+
+            dictionary Foo {
+              Foo1 b;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be a Dictionary that " "inherits from its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              (Foo or DOMString)[]? b;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be a Nullable type "
+        "whose inner type includes its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              (DOMString or Foo) b;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be a Union type, one of "
+        "whose member types includes its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              sequence<sequence<sequence<Foo>>> c;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be a Sequence type "
+        "whose element type includes its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              (DOMString or Foo)[] d;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be an Array type "
+        "whose element type includes its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              Foo1 b;
+            };
+
+            dictionary Foo3 {
+              Foo d;
+            };
+
+            dictionary Foo2 : Foo3 {
+              short c;
+            };
+
+            dictionary Foo1 : Foo2 {
+              long a;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Member type must not be a Dictionary, one of whose "
+        "members or inherited members has a type that includes "
+        "its Dictionary.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+            };
+
+            dictionary Bar {
+              Foo? d;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Member type must not be a nullable dictionary")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary Foo {
+          unrestricted float  urFloat = 0;
+          unrestricted float  urFloat2 = 1.1;
+          unrestricted float  urFloat3 = -1.1;
+          unrestricted float? urFloat4 = null;
+          unrestricted float  infUrFloat = Infinity;
+          unrestricted float  negativeInfUrFloat = -Infinity;
+          unrestricted float  nanUrFloat = NaN;
+
+          unrestricted double  urDouble = 0;
+          unrestricted double  urDouble2 = 1.1;
+          unrestricted double  urDouble3 = -1.1;
+          unrestricted double? urDouble4 = null;
+          unrestricted double  infUrDouble = Infinity;
+          unrestricted double  negativeInfUrDouble = -Infinity;
+          unrestricted double  nanUrDouble = NaN;
+        };
+    """
+    )
+    parser.finish()
+    harness.ok(True, "Parsing default values for unrestricted types succeeded.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              double f = Infinity;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to Infinity")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              double f = -Infinity;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to -Infinity")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              double f = NaN;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to NaN")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              float f = Infinity;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to Infinity")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              float f = -Infinity;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to -Infinity")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              float f = NaN;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Only unrestricted values can be initialized to NaN")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Foo {
+              long module;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(not threw, "Should be able to use 'module' as a dictionary member name")
diff --git a/dom/bindings/parser/tests/test_distinguishability.py b/dom/bindings/parser/tests/test_distinguishability.py
new file mode 100644
index 0000000000..8497490b1f
--- /dev/null
+++ b/dom/bindings/parser/tests/test_distinguishability.py
@@ -0,0 +1,424 @@
+import WebIDL
+
+
+def firstArgType(method):
+    return method.signatures()[0][1][0].type
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      // Give our dictionary a required member so we don't need to
+      // mess with optional and default values.
+      dictionary Dict {
+        required long member;
+      };
+      callback interface Foo {
+      };
+      interface Bar {
+        // Bit of a pain to get things that have dictionary types
+        undefined passDict(Dict arg);
+        undefined passFoo(Foo arg);
+        undefined passNullableUnion((object? or DOMString) arg);
+        undefined passNullable(Foo? arg);
+      };
+    """
+    )
+    results = parser.finish()
+
+    iface = results[2]
+    harness.ok(iface.isInterface(), "Should have interface")
+    dictMethod = iface.members[0]
+    ifaceMethod = iface.members[1]
+    nullableUnionMethod = iface.members[2]
+    nullableIfaceMethod = iface.members[3]
+
+    dictType = firstArgType(dictMethod)
+    ifaceType = firstArgType(ifaceMethod)
+
+    harness.ok(dictType.isDictionary(), "Should have dictionary type")
+    harness.ok(ifaceType.isInterface(), "Should have interface type")
+    harness.ok(ifaceType.isCallbackInterface(), "Should have callback interface type")
+
+    harness.ok(
+        not dictType.isDistinguishableFrom(ifaceType),
+        "Dictionary not distinguishable from callback interface",
+    )
+    harness.ok(
+        not ifaceType.isDistinguishableFrom(dictType),
+        "Callback interface not distinguishable from dictionary",
+    )
+
+    nullableUnionType = firstArgType(nullableUnionMethod)
+    nullableIfaceType = firstArgType(nullableIfaceMethod)
+
+    harness.ok(nullableUnionType.isUnion(), "Should have union type")
+    harness.ok(nullableIfaceType.isInterface(), "Should have interface type")
+    harness.ok(nullableIfaceType.nullable(), "Should have nullable type")
+
+    harness.ok(
+        not nullableUnionType.isDistinguishableFrom(nullableIfaceType),
+        "Nullable type not distinguishable from union with nullable " "member type",
+    )
+    harness.ok(
+        not nullableIfaceType.isDistinguishableFrom(nullableUnionType),
+        "Union with nullable member type not distinguishable from " "nullable type",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      interface TestIface {
+        undefined passKid(Kid arg);
+        undefined passParent(Parent arg);
+        undefined passGrandparent(Grandparent arg);
+        undefined passUnrelated1(Unrelated1 arg);
+        undefined passUnrelated2(Unrelated2 arg);
+        undefined passArrayBuffer(ArrayBuffer arg);
+        undefined passArrayBuffer(ArrayBufferView arg);
+      };
+
+      interface Kid : Parent {};
+      interface Parent : Grandparent {};
+      interface Grandparent {};
+      interface Unrelated1 {};
+      interface Unrelated2 {};
+    """
+    )
+    results = parser.finish()
+
+    iface = results[0]
+    harness.ok(iface.isInterface(), "Should have interface")
+    argTypes = [firstArgType(method) for method in iface.members]
+    unrelatedTypes = [firstArgType(method) for method in iface.members[-3:]]
+
+    for type1 in argTypes:
+        for type2 in argTypes:
+            distinguishable = type1 is not type2 and (
+                type1 in unrelatedTypes or type2 in unrelatedTypes
+            )
+
+            harness.check(
+                type1.isDistinguishableFrom(type2),
+                distinguishable,
+                "Type %s should %sbe distinguishable from type %s"
+                % (type1, "" if distinguishable else "not ", type2),
+            )
+            harness.check(
+                type2.isDistinguishableFrom(type1),
+                distinguishable,
+                "Type %s should %sbe distinguishable from type %s"
+                % (type2, "" if distinguishable else "not ", type1),
+            )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      interface Dummy {};
+      interface TestIface {
+        undefined method(long arg1, TestIface arg2);
+        undefined method(long arg1, long arg2);
+        undefined method(long arg1, Dummy arg2);
+        undefined method(DOMString arg1, DOMString arg2, DOMString arg3);
+      };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results[1].members), 1, "Should look like we have one method")
+    harness.check(
+        len(results[1].members[0].signatures()), 4, "Should have four signatures"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Dummy {};
+          interface TestIface {
+            undefined method(long arg1, TestIface arg2);
+            undefined method(long arg1, long arg2);
+            undefined method(any arg1,  Dummy arg2);
+            undefined method(DOMString arg1, DOMString arg2, DOMString arg3);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should throw when args before the distinguishing arg are not "
+        "all the same type",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Dummy {};
+          interface TestIface {
+            undefined method(long arg1, TestIface arg2);
+            undefined method(long arg1, long arg2);
+            undefined method(any arg1,  DOMString arg2);
+            undefined method(DOMString arg1, DOMString arg2, DOMString arg3);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should throw when there is no distinguishing index")
+
+    # Now let's test our whole distinguishability table
+    argTypes = [
+        "long",
+        "short",
+        "long?",
+        "short?",
+        "boolean",
+        "boolean?",
+        "undefined",
+        "undefined?",
+        "DOMString",
+        "ByteString",
+        "UTF8String",
+        "Enum",
+        "Enum2",
+        "Interface",
+        "Interface?",
+        "AncestorInterface",
+        "UnrelatedInterface",
+        "CallbackInterface",
+        "CallbackInterface?",
+        "CallbackInterface2",
+        "object",
+        "Callback",
+        "Callback2",
+        "Dict",
+        "Dict2",
+        "sequence<long>",
+        "sequence<short>",
+        "record<DOMString, object>",
+        "record<USVString, Dict>",
+        "record<ByteString, long>",
+        "record<UTF8String, long>",
+        "any",
+        "Promise<any>",
+        "Promise<any>?",
+        "USVString",
+        "JSString",
+        "ArrayBuffer",
+        "ArrayBufferView",
+        "Uint8Array",
+        "Uint16Array",
+        "(long or Callback)",
+        "(long or Dict)",
+    ]
+
+    # Try to categorize things a bit to keep list lengths down
+    def allBut(list1, list2):
+        return [
+            a
+            for a in list1
+            if a not in list2
+            and (a != "any" and a != "Promise<any>" and a != "Promise<any>?")
+        ]
+
+    unions = ["(long or Callback)", "(long or Dict)"]
+    numerics = ["long", "short", "long?", "short?"]
+    booleans = ["boolean", "boolean?"]
+    undefineds = ["undefined", "undefined?"]
+    primitives = numerics + booleans
+    nonNumerics = allBut(argTypes, numerics + unions)
+    nonBooleans = allBut(argTypes, booleans)
+    strings = [
+        "DOMString",
+        "ByteString",
+        "Enum",
+        "Enum2",
+        "USVString",
+        "JSString",
+        "UTF8String",
+    ]
+    nonStrings = allBut(argTypes, strings)
+    nonObjects = undefineds + primitives + strings
+    bufferSourceTypes = ["ArrayBuffer", "ArrayBufferView", "Uint8Array", "Uint16Array"]
+    interfaces = [
+        "Interface",
+        "Interface?",
+        "AncestorInterface",
+        "UnrelatedInterface",
+    ] + bufferSourceTypes
+    nullables = [
+        "long?",
+        "short?",
+        "boolean?",
+        "undefined?",
+        "Interface?",
+        "CallbackInterface?",
+        "Dict",
+        "Dict2",
+        "Date?",
+        "any",
+        "Promise<any>?",
+    ] + allBut(unions, ["(long or Callback)"])
+    sequences = ["sequence<long>", "sequence<short>"]
+    nonUserObjects = nonObjects + interfaces + sequences
+    otherObjects = allBut(argTypes, nonUserObjects + ["object"])
+    notRelatedInterfaces = (
+        nonObjects
+        + ["UnrelatedInterface"]
+        + otherObjects
+        + sequences
+        + bufferSourceTypes
+    )
+    records = [
+        "record<DOMString, object>",
+        "record<USVString, Dict>",
+        "record<ByteString, long>",
+        "record<UTF8String, long>",
+    ]  # JSString not supported in records
+    dictionaryLike = (
+        [
+            "Dict",
+            "Dict2",
+            "CallbackInterface",
+            "CallbackInterface?",
+            "CallbackInterface2",
+        ]
+        + records
+        + allBut(unions, ["(long or Callback)"])
+    )
+
+    # Build a representation of the distinguishability table as a dict
+    # of dicts, holding True values where needed, holes elsewhere.
+    data = dict()
+    for type in argTypes:
+        data[type] = dict()
+
+    def setDistinguishable(type, types):
+        for other in types:
+            data[type][other] = True
+
+    setDistinguishable("long", nonNumerics)
+    setDistinguishable("short", nonNumerics)
+    setDistinguishable("long?", allBut(nonNumerics, nullables))
+    setDistinguishable("short?", allBut(nonNumerics, nullables))
+    setDistinguishable("boolean", nonBooleans)
+    setDistinguishable("boolean?", allBut(nonBooleans, nullables))
+    setDistinguishable("undefined", allBut(argTypes, undefineds + dictionaryLike))
+    setDistinguishable(
+        "undefined?", allBut(argTypes, undefineds + dictionaryLike + nullables)
+    )
+    setDistinguishable("DOMString", nonStrings)
+    setDistinguishable("ByteString", nonStrings)
+    setDistinguishable("UTF8String", nonStrings)
+    setDistinguishable("USVString", nonStrings)
+    setDistinguishable("JSString", nonStrings)
+    setDistinguishable("Enum", nonStrings)
+    setDistinguishable("Enum2", nonStrings)
+    setDistinguishable("Interface", notRelatedInterfaces)
+    setDistinguishable("Interface?", allBut(notRelatedInterfaces, nullables))
+    setDistinguishable("AncestorInterface", notRelatedInterfaces)
+    setDistinguishable(
+        "UnrelatedInterface", allBut(argTypes, ["object", "UnrelatedInterface"])
+    )
+    setDistinguishable("CallbackInterface", allBut(nonUserObjects, undefineds))
+    setDistinguishable(
+        "CallbackInterface?", allBut(nonUserObjects, nullables + undefineds)
+    )
+    setDistinguishable("CallbackInterface2", allBut(nonUserObjects, undefineds))
+    setDistinguishable("object", nonObjects)
+    setDistinguishable("Callback", nonUserObjects)
+    setDistinguishable("Callback2", nonUserObjects)
+    setDistinguishable("Dict", allBut(nonUserObjects, nullables + undefineds))
+    setDistinguishable("Dict2", allBut(nonUserObjects, nullables + undefineds))
+    setDistinguishable("sequence<long>", allBut(argTypes, sequences + ["object"]))
+    setDistinguishable("sequence<short>", allBut(argTypes, sequences + ["object"]))
+    setDistinguishable("record<DOMString, object>", allBut(nonUserObjects, undefineds))
+    setDistinguishable("record<USVString, Dict>", allBut(nonUserObjects, undefineds))
+    # JSString not supported in records
+    setDistinguishable("record<ByteString, long>", allBut(nonUserObjects, undefineds))
+    setDistinguishable("record<UTF8String, long>", allBut(nonUserObjects, undefineds))
+    setDistinguishable("any", [])
+    setDistinguishable("Promise<any>", [])
+    setDistinguishable("Promise<any>?", [])
+    setDistinguishable("ArrayBuffer", allBut(argTypes, ["ArrayBuffer", "object"]))
+    setDistinguishable(
+        "ArrayBufferView",
+        allBut(argTypes, ["ArrayBufferView", "Uint8Array", "Uint16Array", "object"]),
+    )
+    setDistinguishable(
+        "Uint8Array", allBut(argTypes, ["ArrayBufferView", "Uint8Array", "object"])
+    )
+    setDistinguishable(
+        "Uint16Array", allBut(argTypes, ["ArrayBufferView", "Uint16Array", "object"])
+    )
+    setDistinguishable("(long or Callback)", allBut(nonUserObjects, numerics))
+    setDistinguishable(
+        "(long or Dict)", allBut(nonUserObjects, numerics + nullables + undefineds)
+    )
+
+    def areDistinguishable(type1, type2):
+        return data[type1].get(type2, False)
+
+    def checkDistinguishability(parser, type1, type2):
+        idlTemplate = """
+          enum Enum { "a", "b" };
+          enum Enum2 { "c", "d" };
+          interface Interface : AncestorInterface {};
+          interface AncestorInterface {};
+          interface UnrelatedInterface {};
+          callback interface CallbackInterface {};
+          callback interface CallbackInterface2 {};
+          callback Callback = any();
+          callback Callback2 = long(short arg);
+          // Give our dictionaries required members so we don't need to
+          // mess with optional and default values.
+          dictionary Dict { required long member; };
+          dictionary Dict2 { required long member; };
+          interface TestInterface {%s
+          };
+        """
+        if type1 in undefineds or type2 in undefineds:
+            methods = """
+                (%s or %s) myMethod();""" % (
+                type1,
+                type2,
+            )
+        else:
+            methodTemplate = """
+                undefined myMethod(%s arg);"""
+            methods = (methodTemplate % type1) + (methodTemplate % type2)
+        idl = idlTemplate % methods
+
+        parser = parser.reset()
+        threw = False
+        try:
+            parser.parse(idl)
+            parser.finish()
+        except WebIDL.WebIDLError:
+            threw = True
+
+        if areDistinguishable(type1, type2):
+            harness.ok(
+                not threw,
+                "Should not throw for '%s' and '%s' because they are distinguishable"
+                % (type1, type2),
+            )
+        else:
+            harness.ok(
+                threw,
+                "Should throw for '%s' and '%s' because they are not distinguishable"
+                % (type1, type2),
+            )
+
+    # Enumerate over everything in both orders, since order matters in
+    # terms of our implementation of distinguishability checks
+    for type1 in argTypes:
+        for type2 in argTypes:
+            checkDistinguishability(parser, type1, type2)
diff --git a/dom/bindings/parser/tests/test_double_null.py b/dom/bindings/parser/tests/test_double_null.py
new file mode 100644
index 0000000000..28166020c1
--- /dev/null
+++ b/dom/bindings/parser/tests/test_double_null.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DoubleNull {
+              attribute byte?? foo;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_duplicate_qualifiers.py b/dom/bindings/parser/tests/test_duplicate_qualifiers.py
new file mode 100644
index 0000000000..bb02f96acf
--- /dev/null
+++ b/dom/bindings/parser/tests/test_duplicate_qualifiers.py
@@ -0,0 +1,67 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DuplicateQualifiers1 {
+              getter getter byte foo(unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DuplicateQualifiers2 {
+              setter setter byte foo(unsigned long index, byte value);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DuplicateQualifiers4 {
+              deleter deleter byte foo(unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DuplicateQualifiers5 {
+              getter deleter getter byte foo(unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_empty_enum.py b/dom/bindings/parser/tests/test_empty_enum.py
new file mode 100644
index 0000000000..ad002caa4e
--- /dev/null
+++ b/dom/bindings/parser/tests/test_empty_enum.py
@@ -0,0 +1,17 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    try:
+        parser.parse(
+            """
+            enum TestEmptyEnum {
+            };
+        """
+        )
+
+        harness.ok(False, "Should have thrown!")
+    except WebIDL.WebIDLError:
+        harness.ok(True, "Parsing TestEmptyEnum enum should fail")
+
+    parser.finish()
diff --git a/dom/bindings/parser/tests/test_empty_sequence_default_value.py b/dom/bindings/parser/tests/test_empty_sequence_default_value.py
new file mode 100644
index 0000000000..4771a6b1e5
--- /dev/null
+++ b/dom/bindings/parser/tests/test_empty_sequence_default_value.py
@@ -0,0 +1,54 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface X {
+              const sequence<long> foo = [];
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Constant cannot have [] as a default value")
+
+    parser = parser.reset()
+
+    parser.parse(
+        """
+        interface X {
+          undefined foo(optional sequence<long> arg = []);
+        };
+    """
+    )
+    results = parser.finish()
+
+    harness.ok(
+        isinstance(
+            results[0].members[0].signatures()[0][1][0].defaultValue,
+            WebIDL.IDLEmptySequenceValue,
+        ),
+        "Should have IDLEmptySequenceValue as default value of argument",
+    )
+
+    parser = parser.reset()
+
+    parser.parse(
+        """
+        dictionary X {
+          sequence<long> foo = [];
+        };
+    """
+    )
+    results = parser.finish()
+
+    harness.ok(
+        isinstance(results[0].members[0].defaultValue, WebIDL.IDLEmptySequenceValue),
+        "Should have IDLEmptySequenceValue as default value of " "dictionary member",
+    )
diff --git a/dom/bindings/parser/tests/test_enum.py b/dom/bindings/parser/tests/test_enum.py
new file mode 100644
index 0000000000..4eb26f7eaf
--- /dev/null
+++ b/dom/bindings/parser/tests/test_enum.py
@@ -0,0 +1,107 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        enum TestEnum {
+          "",
+          "foo",
+          "bar"
+        };
+
+        interface TestEnumInterface {
+          TestEnum doFoo(boolean arg);
+          readonly attribute TestEnum foo;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestEnumInterfaces interface parsed without error.")
+    harness.check(len(results), 2, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLEnum), "Should be an IDLEnum")
+    harness.ok(isinstance(results[1], WebIDL.IDLInterface), "Should be an IDLInterface")
+
+    enum = results[0]
+    harness.check(enum.identifier.QName(), "::TestEnum", "Enum has the right QName")
+    harness.check(enum.identifier.name, "TestEnum", "Enum has the right name")
+    harness.check(enum.values(), ["", "foo", "bar"], "Enum has the right values")
+
+    iface = results[1]
+
+    harness.check(
+        iface.identifier.QName(), "::TestEnumInterface", "Interface has the right QName"
+    )
+    harness.check(
+        iface.identifier.name, "TestEnumInterface", "Interface has the right name"
+    )
+    harness.check(iface.parent, None, "Interface has no parent")
+
+    members = iface.members
+    harness.check(len(members), 2, "Should be one production")
+    harness.ok(isinstance(members[0], WebIDL.IDLMethod), "Should be an IDLMethod")
+    method = members[0]
+    harness.check(
+        method.identifier.QName(),
+        "::TestEnumInterface::doFoo",
+        "Method has correct QName",
+    )
+    harness.check(method.identifier.name, "doFoo", "Method has correct name")
+
+    signatures = method.signatures()
+    harness.check(len(signatures), 1, "Expect one signature")
+
+    (returnType, arguments) = signatures[0]
+    harness.check(
+        str(returnType), "TestEnum (Wrapper)", "Method type is the correct name"
+    )
+    harness.check(len(arguments), 1, "Method has the right number of arguments")
+    arg = arguments[0]
+    harness.ok(isinstance(arg, WebIDL.IDLArgument), "Should be an IDLArgument")
+    harness.check(str(arg.type), "Boolean", "Argument has the right type")
+
+    attr = members[1]
+    harness.check(
+        attr.identifier.QName(), "::TestEnumInterface::foo", "Attr has correct QName"
+    )
+    harness.check(attr.identifier.name, "foo", "Attr has correct name")
+
+    harness.check(str(attr.type), "TestEnum (Wrapper)", "Attr type is the correct name")
+
+    # Now reset our parser
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          enum Enum {
+            "a",
+            "b",
+            "c"
+          };
+          interface TestInterface {
+            undefined foo(optional Enum e = "d");
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow a bogus default value for an enum")
+
+    # Now reset our parser
+    parser = parser.reset()
+    parser.parse(
+        """
+      enum Enum {
+        "a",
+        "b",
+        "c",
+      };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should allow trailing comma in enum")
diff --git a/dom/bindings/parser/tests/test_enum_duplicate_values.py b/dom/bindings/parser/tests/test_enum_duplicate_values.py
new file mode 100644
index 0000000000..f40a178442
--- /dev/null
+++ b/dom/bindings/parser/tests/test_enum_duplicate_values.py
@@ -0,0 +1,16 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    try:
+        parser.parse(
+            """
+            enum TestEnumDuplicateValue {
+              "",
+              ""
+            };
+        """
+        )
+        harness.ok(False, "Should have thrown!")
+    except WebIDL.WebIDLError:
+        harness.ok(True, "Enum TestEnumDuplicateValue should throw")
diff --git a/dom/bindings/parser/tests/test_error_colno.py b/dom/bindings/parser/tests/test_error_colno.py
new file mode 100644
index 0000000000..b08ba7cc17
--- /dev/null
+++ b/dom/bindings/parser/tests/test_error_colno.py
@@ -0,0 +1,24 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    # Check that error messages put the '^' in the right place.
+
+    threw = False
+    input = "interface ?"
+    try:
+        parser.parse(input)
+        parser.finish()
+    except WebIDL.WebIDLError as e:
+        threw = True
+        lines = str(e).split("\n")
+
+        harness.check(len(lines), 3, "Expected number of lines in error message")
+        harness.check(lines[1], input, "Second line shows error")
+        harness.check(
+            lines[2],
+            " " * (len(input) - 1) + "^",
+            "Correct column pointer in error message",
+        )
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_error_lineno.py b/dom/bindings/parser/tests/test_error_lineno.py
new file mode 100644
index 0000000000..30629be30c
--- /dev/null
+++ b/dom/bindings/parser/tests/test_error_lineno.py
@@ -0,0 +1,38 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    # Check that error messages put the '^' in the right place.
+
+    threw = False
+    input = """\
+// This is a comment.
+interface Foo {
+};
+
+/* This is also a comment. */
+interface ?"""
+    try:
+        parser.parse(input)
+        parser.finish()
+    except WebIDL.WebIDLError as e:
+        threw = True
+        lines = str(e).split("\n")
+
+        harness.check(len(lines), 3, "Expected number of lines in error message")
+        harness.ok(
+            lines[0].endswith("line 6:10"),
+            'First line of error should end with "line 6:10", but was "%s".' % lines[0],
+        )
+        harness.check(
+            lines[1],
+            "interface ?",
+            "Second line of error message is the line which caused the error.",
+        )
+        harness.check(
+            lines[2],
+            " " * (len("interface ?") - 1) + "^",
+            "Correct column pointer in error message.",
+        )
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_exposed_extended_attribute.py b/dom/bindings/parser/tests/test_exposed_extended_attribute.py
new file mode 100644
index 0000000000..51bc96aecc
--- /dev/null
+++ b/dom/bindings/parser/tests/test_exposed_extended_attribute.py
@@ -0,0 +1,383 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      [Global, Exposed=Foo] interface Foo {};
+      [Global=(Bar, Bar1,Bar2), Exposed=Bar] interface Bar {};
+      [Global=(Baz, Baz2), Exposed=Baz] interface Baz {};
+
+      [Exposed=(Foo,Bar1)]
+      interface Iface {
+        undefined method1();
+
+        [Exposed=Bar1]
+        readonly attribute any attr;
+      };
+
+      [Exposed=Foo]
+      partial interface Iface {
+        undefined method2();
+      };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 5, "Should know about five things")
+    iface = results[3]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should have an interface here")
+    members = iface.members
+    harness.check(len(members), 3, "Should have three members")
+
+    harness.ok(
+        members[0].exposureSet == set(["Foo", "Bar"]),
+        "method1 should have the right exposure set",
+    )
+    harness.ok(
+        members[0]._exposureGlobalNames == set(["Foo", "Bar1"]),
+        "method1 should have the right exposure global names",
+    )
+
+    harness.ok(
+        members[1].exposureSet == set(["Bar"]),
+        "attr should have the right exposure set",
+    )
+    harness.ok(
+        members[1]._exposureGlobalNames == set(["Bar1"]),
+        "attr should have the right exposure global names",
+    )
+
+    harness.ok(
+        members[2].exposureSet == set(["Foo"]),
+        "method2 should have the right exposure set",
+    )
+    harness.ok(
+        members[2]._exposureGlobalNames == set(["Foo"]),
+        "method2 should have the right exposure global names",
+    )
+
+    harness.ok(
+        iface.exposureSet == set(["Foo", "Bar"]),
+        "Iface should have the right exposure set",
+    )
+    harness.ok(
+        iface._exposureGlobalNames == set(["Foo", "Bar1"]),
+        "Iface should have the right exposure global names",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      [Global, Exposed=Foo] interface Foo {};
+      [Global=(Bar, Bar1, Bar2), Exposed=Bar] interface Bar {};
+      [Global=(Baz, Baz2), Exposed=Baz] interface Baz {};
+
+      [Exposed=Foo]
+      interface Iface2 {
+        undefined method3();
+      };
+    """
+    )
+    results = parser.finish()
+
+    harness.check(len(results), 4, "Should know about four things")
+    iface = results[3]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should have an interface here")
+    members = iface.members
+    harness.check(len(members), 1, "Should have one member")
+
+    harness.ok(
+        members[0].exposureSet == set(["Foo"]),
+        "method3 should have the right exposure set",
+    )
+    harness.ok(
+        members[0]._exposureGlobalNames == set(["Foo"]),
+        "method3 should have the right exposure global names",
+    )
+
+    harness.ok(
+        iface.exposureSet == set(["Foo"]), "Iface2 should have the right exposure set"
+    )
+    harness.ok(
+        iface._exposureGlobalNames == set(["Foo"]),
+        "Iface2 should have the right exposure global names",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      [Global, Exposed=Foo] interface Foo {};
+      [Global=(Bar, Bar1, Bar2), Exposed=Bar] interface Bar {};
+      [Global=(Baz, Baz2), Exposed=Baz] interface Baz {};
+
+      [Exposed=Foo]
+      interface Iface3 {
+        undefined method4();
+      };
+
+      [Exposed=(Foo,Bar1)]
+      interface mixin Mixin {
+        undefined method5();
+      };
+
+      Iface3 includes Mixin;
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 6, "Should know about six things")
+    iface = results[3]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should have an interface here")
+    members = iface.members
+    harness.check(len(members), 2, "Should have two members")
+
+    harness.ok(
+        members[0].exposureSet == set(["Foo"]),
+        "method4 should have the right exposure set",
+    )
+    harness.ok(
+        members[0]._exposureGlobalNames == set(["Foo"]),
+        "method4 should have the right exposure global names",
+    )
+
+    harness.ok(
+        members[1].exposureSet == set(["Foo", "Bar"]),
+        "method5 should have the right exposure set",
+    )
+    harness.ok(
+        members[1]._exposureGlobalNames == set(["Foo", "Bar1"]),
+        "method5 should have the right exposure global names",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Exposed=Foo]
+            interface Bar {
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on invalid Exposed value on interface.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Bar {
+              [Exposed=Foo]
+              readonly attribute bool attr;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on invalid Exposed value on attribute.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Bar {
+              [Exposed=Foo]
+              undefined operation();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on invalid Exposed value on operation.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Bar {
+              [Exposed=Foo]
+              const long constant = 5;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on invalid Exposed value on constant.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Foo] interface Foo {};
+            [Global, Exposed=Bar] interface Bar {};
+
+            [Exposed=Foo]
+            interface Baz {
+              [Exposed=Bar]
+              undefined method();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should have thrown on member exposed where its interface is not."
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Foo] interface Foo {};
+        [Global, Exposed=Bar] interface Bar {};
+
+        [Exposed=Foo]
+        interface Baz {
+          undefined method();
+        };
+
+        [Exposed=Bar]
+        interface mixin Mixin {
+          undefined otherMethod();
+        };
+
+        Baz includes Mixin;
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 5, "Should know about five things")
+    iface = results[2]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should have an interface here")
+    members = iface.members
+    harness.check(len(members), 2, "Should have two members")
+
+    harness.ok(
+        members[0].exposureSet == set(["Foo"]),
+        "method should have the right exposure set",
+    )
+    harness.ok(
+        members[0]._exposureGlobalNames == set(["Foo"]),
+        "method should have the right exposure global names",
+    )
+
+    harness.ok(
+        members[1].exposureSet == set(["Bar"]),
+        "otherMethod should have the right exposure set",
+    )
+    harness.ok(
+        members[1]._exposureGlobalNames == set(["Bar"]),
+        "otherMethod should have the right exposure global names",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Foo] interface Foo {};
+        [Global, Exposed=Bar] interface Bar {};
+
+        [Exposed=*]
+        interface Baz {
+          undefined methodWild();
+        };
+
+        [Exposed=Bar]
+        interface mixin Mixin {
+          undefined methodNotWild();
+        };
+
+        Baz includes Mixin;
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 5, "Should know about five things")
+    iface = results[2]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should have an interface here")
+    members = iface.members
+    harness.check(len(members), 2, "Should have two members")
+
+    harness.ok(
+        members[0].exposureSet == set(["Foo", "Bar"]),
+        "methodWild should have the right exposure set",
+    )
+    harness.ok(
+        members[0]._exposureGlobalNames == set(["Foo", "Bar"]),
+        "methodWild should have the right exposure global names",
+    )
+
+    harness.ok(
+        members[1].exposureSet == set(["Bar"]),
+        "methodNotWild should have the right exposure set",
+    )
+    harness.ok(
+        members[1]._exposureGlobalNames == set(["Bar"]),
+        "methodNotWild should have the right exposure global names",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Foo] interface Foo {};
+            [Global, Exposed=Bar] interface Bar {};
+
+            [Exposed=Foo]
+            interface Baz {
+              [Exposed=*]
+              undefined method();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should have thrown on member exposed where its interface is not."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Foo] interface Foo {};
+            [Global, Exposed=Bar] interface Bar {};
+
+            [Exposed=(Foo,*)]
+            interface Baz {
+              undefined method();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on a wildcard in an identifier list.")
diff --git a/dom/bindings/parser/tests/test_extended_attributes.py b/dom/bindings/parser/tests/test_extended_attributes.py
new file mode 100644
index 0000000000..96c8ee9acb
--- /dev/null
+++ b/dom/bindings/parser/tests/test_extended_attributes.py
@@ -0,0 +1,131 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        [LegacyNoInterfaceObject]
+        interface TestExtendedAttr {
+          [LegacyUnforgeable] readonly attribute byte b;
+        };
+    """
+    )
+
+    parser.finish()
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Pref="foo.bar",Pref=flop]
+        interface TestExtendedAttr {
+          [Pref="foo.bar"] attribute byte b;
+        };
+    """
+    )
+
+    parser.finish()
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestLegacyLenientThis {
+          [LegacyLenientThis] attribute byte b;
+        };
+    """
+    )
+
+    results = parser.finish()
+    harness.ok(
+        results[0].members[0].hasLegacyLenientThis(), "Should have a lenient this"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestLegacyLenientThis2 {
+              [LegacyLenientThis=something] attribute byte b;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "[LegacyLenientThis] must take no arguments")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestClamp {
+          undefined testClamp([Clamp] long foo);
+          undefined testNotClamp(long foo);
+        };
+    """
+    )
+
+    results = parser.finish()
+    # Pull out the first argument out of the arglist of the first (and
+    # only) signature.
+    harness.ok(
+        results[0].members[0].signatures()[0][1][0].type.hasClamp(), "Should be clamped"
+    )
+    harness.ok(
+        not results[0].members[1].signatures()[0][1][0].type.hasClamp(),
+        "Should not be clamped",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestClamp2 {
+              undefined testClamp([Clamp=something] long foo);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "[Clamp] must take no arguments")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestEnforceRange {
+          undefined testEnforceRange([EnforceRange] long foo);
+          undefined testNotEnforceRange(long foo);
+        };
+    """
+    )
+
+    results = parser.finish()
+    # Pull out the first argument out of the arglist of the first (and
+    # only) signature.
+    harness.ok(
+        results[0].members[0].signatures()[0][1][0].type.hasEnforceRange(),
+        "Should be enforceRange",
+    )
+    harness.ok(
+        not results[0].members[1].signatures()[0][1][0].type.hasEnforceRange(),
+        "Should not be enforceRange",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestEnforceRange2 {
+              undefined testEnforceRange([EnforceRange=something] long foo);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "[EnforceRange] must take no arguments")
diff --git a/dom/bindings/parser/tests/test_float_types.py b/dom/bindings/parser/tests/test_float_types.py
new file mode 100644
index 0000000000..1b3b6556d8
--- /dev/null
+++ b/dom/bindings/parser/tests/test_float_types.py
@@ -0,0 +1,145 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        typedef float myFloat;
+        typedef unrestricted float myUnrestrictedFloat;
+        interface FloatTypes {
+          attribute float f;
+          attribute unrestricted float uf;
+          attribute double d;
+          attribute unrestricted double ud;
+          [LenientFloat]
+          attribute float lf;
+          [LenientFloat]
+          attribute double ld;
+
+          undefined m1(float arg1, double arg2, float? arg3, double? arg4,
+                       myFloat arg5, unrestricted float arg6,
+                       unrestricted double arg7, unrestricted float? arg8,
+                       unrestricted double? arg9, myUnrestrictedFloat arg10);
+          [LenientFloat]
+          undefined m2(float arg1, double arg2, float? arg3, double? arg4,
+                       myFloat arg5, unrestricted float arg6,
+                       unrestricted double arg7, unrestricted float? arg8,
+                       unrestricted double? arg9, myUnrestrictedFloat arg10);
+          [LenientFloat]
+          undefined m3(float arg);
+          [LenientFloat]
+          undefined m4(double arg);
+          [LenientFloat]
+          undefined m5((float or FloatTypes) arg);
+          [LenientFloat]
+          undefined m6(sequence<float> arg);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 3, "Should be two typedefs and one interface.")
+    iface = results[2]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    types = [a.type for a in iface.members if a.isAttr()]
+    harness.ok(types[0].isFloat(), "'float' is a float")
+    harness.ok(not types[0].isUnrestricted(), "'float' is not unrestricted")
+    harness.ok(types[1].isFloat(), "'unrestricted float' is a float")
+    harness.ok(types[1].isUnrestricted(), "'unrestricted float' is unrestricted")
+    harness.ok(types[2].isFloat(), "'double' is a float")
+    harness.ok(not types[2].isUnrestricted(), "'double' is not unrestricted")
+    harness.ok(types[3].isFloat(), "'unrestricted double' is a float")
+    harness.ok(types[3].isUnrestricted(), "'unrestricted double' is unrestricted")
+
+    method = iface.members[6]
+    harness.ok(isinstance(method, WebIDL.IDLMethod), "Should be an IDLMethod")
+    argtypes = [a.type for a in method.signatures()[0][1]]
+    for idx, type in enumerate(argtypes):
+        harness.ok(type.isFloat(), "Type %d should be float" % idx)
+        harness.check(
+            type.isUnrestricted(),
+            idx >= 5,
+            "Type %d should %sbe unrestricted" % (idx, "" if idx >= 4 else "not "),
+        )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface FloatTypes {
+              [LenientFloat]
+              long m(float arg);
+            };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[LenientFloat] only allowed on methods returning undefined")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface FloatTypes {
+              [LenientFloat]
+              undefined m(unrestricted float arg);
+            };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "[LenientFloat] only allowed on methods with unrestricted float args"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface FloatTypes {
+              [LenientFloat]
+              undefined m(sequence<unrestricted float> arg);
+            };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "[LenientFloat] only allowed on methods with unrestricted float args (2)"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface FloatTypes {
+              [LenientFloat]
+              undefined m((unrestricted float or FloatTypes) arg);
+            };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "[LenientFloat] only allowed on methods with unrestricted float args (3)"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface FloatTypes {
+              [LenientFloat]
+              readonly attribute float foo;
+            };
+        """
+        )
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[LenientFloat] only allowed on writable attributes")
diff --git a/dom/bindings/parser/tests/test_forward_decl.py b/dom/bindings/parser/tests/test_forward_decl.py
new file mode 100644
index 0000000000..1ba19e42fc
--- /dev/null
+++ b/dom/bindings/parser/tests/test_forward_decl.py
@@ -0,0 +1,15 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface ForwardDeclared;
+        interface ForwardDeclared;
+
+        interface TestForwardDecl {
+          attribute ForwardDeclared foo;
+        };
+    """
+    )
+
+    parser.finish()
+
+    harness.ok(True, "TestForwardDeclared interface parsed without error.")
diff --git a/dom/bindings/parser/tests/test_global_extended_attr.py b/dom/bindings/parser/tests/test_global_extended_attr.py
new file mode 100644
index 0000000000..54b8ec0d7a
--- /dev/null
+++ b/dom/bindings/parser/tests/test_global_extended_attr.py
@@ -0,0 +1,132 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      [Global, Exposed=Foo]
+      interface Foo : Bar {
+        getter any(DOMString name);
+      };
+      [Exposed=Foo]
+      interface Bar {};
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(
+        results[0].isOnGlobalProtoChain(),
+        "[Global] interface should be on global's proto chain",
+    )
+    harness.ok(
+        results[1].isOnGlobalProtoChain(),
+        "[Global] interface should be on global's proto chain",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          [Global, Exposed=Foo]
+          interface Foo {
+            getter any(DOMString name);
+            setter undefined(DOMString name, any arg);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown for [Global] used on an interface with a " "named setter",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          [Global, Exposed=Foo]
+          interface Foo {
+            getter any(DOMString name);
+            deleter undefined(DOMString name);
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown for [Global] used on an interface with a " "named deleter",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          [Global, LegacyOverrideBuiltIns, Exposed=Foo]
+          interface Foo {
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown for [Global] used on an interface with a "
+        "[LegacyOverrideBuiltIns]",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          [Global, Exposed=Foo]
+          interface Foo : Bar {
+          };
+          [LegacyOverrideBuiltIns, Exposed=Foo]
+          interface Bar {
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown for [Global] used on an interface with an "
+        "[LegacyOverrideBuiltIns] ancestor",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          [Global, Exposed=Foo]
+          interface Foo {
+          };
+          [Exposed=Foo]
+          interface Bar : Foo {
+          };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown for [Global] used on an interface with a " "descendant",
+    )
diff --git a/dom/bindings/parser/tests/test_identifier_conflict.py b/dom/bindings/parser/tests/test_identifier_conflict.py
new file mode 100644
index 0000000000..424f4d6285
--- /dev/null
+++ b/dom/bindings/parser/tests/test_identifier_conflict.py
@@ -0,0 +1,45 @@
+def WebIDLTest(parser, harness):
+    try:
+        parser.parse(
+            """
+            enum Foo { "a" };
+            interface Foo;
+        """
+        )
+        parser.finish()
+        harness.ok(False, "Should fail to parse")
+    except Exception as e:
+        harness.ok(
+            "Name collision" in str(e), "Should have name collision for interface"
+        )
+
+    parser = parser.reset()
+    try:
+        parser.parse(
+            """
+            dictionary Foo { long x; };
+            enum Foo { "a" };
+        """
+        )
+        parser.finish()
+        harness.ok(False, "Should fail to parse")
+    except Exception as e:
+        harness.ok(
+            "Name collision" in str(e), "Should have name collision for dictionary"
+        )
+
+    parser = parser.reset()
+    try:
+        parser.parse(
+            """
+            enum Foo { "a" };
+            enum Foo { "b" };
+        """
+        )
+        parser.finish()
+        harness.ok(False, "Should fail to parse")
+    except Exception as e:
+        harness.ok(
+            "Multiple unresolvable definitions" in str(e),
+            "Should have name collision for dictionary",
+        )
diff --git a/dom/bindings/parser/tests/test_incomplete_parent.py b/dom/bindings/parser/tests/test_incomplete_parent.py
new file mode 100644
index 0000000000..80662a7848
--- /dev/null
+++ b/dom/bindings/parser/tests/test_incomplete_parent.py
@@ -0,0 +1,18 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestIncompleteParent : NotYetDefined {
+          undefined foo();
+        };
+
+        interface NotYetDefined : EvenHigherOnTheChain {
+        };
+
+        interface EvenHigherOnTheChain {
+        };
+    """
+    )
+
+    parser.finish()
+
+    harness.ok(True, "TestIncompleteParent interface parsed without error.")
diff --git a/dom/bindings/parser/tests/test_incomplete_types.py b/dom/bindings/parser/tests/test_incomplete_types.py
new file mode 100644
index 0000000000..0d54f708bb
--- /dev/null
+++ b/dom/bindings/parser/tests/test_incomplete_types.py
@@ -0,0 +1,61 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestIncompleteTypes {
+          attribute FooInterface attr1;
+
+          FooInterface method1(FooInterface arg);
+        };
+
+        interface FooInterface {
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestIncompleteTypes interface parsed without error.")
+    harness.check(len(results), 2, "Should be two productions.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(),
+        "::TestIncompleteTypes",
+        "Interface has the right QName",
+    )
+    harness.check(
+        iface.identifier.name, "TestIncompleteTypes", "Interface has the right name"
+    )
+    harness.check(len(iface.members), 2, "Expect 2 members")
+
+    attr = iface.members[0]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    method = iface.members[1]
+    harness.ok(isinstance(method, WebIDL.IDLMethod), "Should be an IDLMethod")
+
+    harness.check(
+        attr.identifier.QName(),
+        "::TestIncompleteTypes::attr1",
+        "Attribute has the right QName",
+    )
+    harness.check(
+        attr.type.name, "FooInterface", "Previously unresolved type has the right name"
+    )
+
+    harness.check(
+        method.identifier.QName(),
+        "::TestIncompleteTypes::method1",
+        "Attribute has the right QName",
+    )
+    (returnType, args) = method.signatures()[0]
+    harness.check(
+        returnType.name, "FooInterface", "Previously unresolved type has the right name"
+    )
+    harness.check(
+        args[0].type.name,
+        "FooInterface",
+        "Previously unresolved type has the right name",
+    )
diff --git a/dom/bindings/parser/tests/test_interface.py b/dom/bindings/parser/tests/test_interface.py
new file mode 100644
index 0000000000..4c1a88a7d5
--- /dev/null
+++ b/dom/bindings/parser/tests/test_interface.py
@@ -0,0 +1,459 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse("interface Foo { };")
+    results = parser.finish()
+    harness.ok(True, "Empty interface parsed without error.")
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+    iface = results[0]
+    harness.check(iface.identifier.QName(), "::Foo", "Interface has the right QName")
+    harness.check(iface.identifier.name, "Foo", "Interface has the right name")
+    harness.check(iface.parent, None, "Interface has no parent")
+
+    parser.parse("interface Bar : Foo { };")
+    results = parser.finish()
+    harness.ok(True, "Empty interface parsed without error.")
+    harness.check(len(results), 2, "Should be two productions")
+    harness.ok(isinstance(results[1], WebIDL.IDLInterface), "Should be an IDLInterface")
+    iface = results[1]
+    harness.check(iface.identifier.QName(), "::Bar", "Interface has the right QName")
+    harness.check(iface.identifier.name, "Bar", "Interface has the right name")
+    harness.ok(isinstance(iface.parent, WebIDL.IDLInterface), "Interface has a parent")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface QNameBase {
+          attribute long foo;
+        };
+
+        interface QNameDerived : QNameBase {
+          attribute long long foo;
+          attribute byte bar;
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 2, "Should be two productions")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.ok(isinstance(results[1], WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(results[1].parent, results[0], "Inheritance chain is right")
+    harness.check(len(results[0].members), 1, "Expect 1 productions")
+    harness.check(len(results[1].members), 2, "Expect 2 productions")
+    base = results[0]
+    derived = results[1]
+    harness.check(
+        base.members[0].identifier.QName(),
+        "::QNameBase::foo",
+        "Member has the right QName",
+    )
+    harness.check(
+        derived.members[0].identifier.QName(),
+        "::QNameDerived::foo",
+        "Member has the right QName",
+    )
+    harness.check(
+        derived.members[1].identifier.QName(),
+        "::QNameDerived::bar",
+        "Member has the right QName",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A : B {};
+            interface B : A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow cycles in interface inheritance chains")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A : C {};
+            interface C : B {};
+            interface B : A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw, "Should not allow indirect cycles in interface inheritance chains"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A;
+            interface B : A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should not allow inheriting from an interface that is only forward declared",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface A {
+            constructor();
+            constructor(long arg);
+            readonly attribute boolean x;
+            undefined foo();
+        };
+        partial interface A {
+            readonly attribute boolean y;
+            undefined foo(long arg);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 2, "Should have two results with partial interface")
+    iface = results[0]
+    harness.check(
+        len(iface.members), 3, "Should have three members with partial interface"
+    )
+    harness.check(
+        iface.members[0].identifier.name,
+        "x",
+        "First member should be x with partial interface",
+    )
+    harness.check(
+        iface.members[1].identifier.name,
+        "foo",
+        "Second member should be foo with partial interface",
+    )
+    harness.check(
+        len(iface.members[1].signatures()),
+        2,
+        "Should have two foo signatures with partial interface",
+    )
+    harness.check(
+        iface.members[2].identifier.name,
+        "y",
+        "Third member should be y with partial interface",
+    )
+    harness.check(
+        len(iface.ctor().signatures()),
+        2,
+        "Should have two constructors with partial interface",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        partial interface A {
+            readonly attribute boolean y;
+            undefined foo(long arg);
+        };
+        interface A {
+            constructor();
+            constructor(long arg);
+            readonly attribute boolean x;
+            undefined foo();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results), 2, "Should have two results with reversed partial interface"
+    )
+    iface = results[1]
+    harness.check(
+        len(iface.members),
+        3,
+        "Should have three members with reversed partial interface",
+    )
+    harness.check(
+        iface.members[0].identifier.name,
+        "x",
+        "First member should be x with reversed partial interface",
+    )
+    harness.check(
+        iface.members[1].identifier.name,
+        "foo",
+        "Second member should be foo with reversed partial interface",
+    )
+    harness.check(
+        len(iface.members[1].signatures()),
+        2,
+        "Should have two foo signatures with reversed partial interface",
+    )
+    harness.check(
+        iface.members[2].identifier.name,
+        "y",
+        "Third member should be y with reversed partial interface",
+    )
+    harness.check(
+        len(iface.ctor().signatures()),
+        2,
+        "Should have two constructors with reversed partial interface",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+                readonly attribute boolean x;
+            };
+            interface A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow two non-partial interfaces with the same name")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            partial interface A {
+                readonly attribute boolean x;
+            };
+            partial interface A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Must have a non-partial interface for a given name")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary  A {
+                boolean x;
+            };
+            partial interface A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between partial interface "
+        "and other object",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+                boolean x;
+            };
+            interface A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow a name collision between interface " "and other object"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+                boolean x;
+            };
+            interface A;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between external interface "
+        "and other object",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+                readonly attribute boolean x;
+            };
+            interface A;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between external interface " "and interface",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface A;
+        interface A;
+    """
+    )
+    results = parser.finish()
+    harness.ok(
+        len(results) == 1 and isinstance(results[0], WebIDL.IDLExternalInterface),
+        "Should allow name collisions between external interface " "declarations",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SomeRandomAnnotation]
+            interface A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow unknown extended attributes on interfaces")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Window] interface Window {};
+        [Exposed=Window, LegacyWindowAlias=A]
+        interface B {};
+        [Exposed=Window, LegacyWindowAlias=(C, D)]
+        interface E {};
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        results[1].legacyWindowAliases, ["A"], "Should support a single identifier"
+    )
+    harness.check(
+        results[2].legacyWindowAliases, ["C", "D"], "Should support an identifier list"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyWindowAlias]
+            interface A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [LegacyWindowAlias] with no value")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Exposed=Worker, LegacyWindowAlias=B]
+            interface A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [LegacyWindowAlias] without Window exposure")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Window] interface Window {};
+            [Exposed=Window]
+            interface A {};
+            [Exposed=Window, LegacyWindowAlias=A]
+            interface B {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow [LegacyWindowAlias] to conflict with other identifiers"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Window] interface Window {};
+            [Exposed=Window, LegacyWindowAlias=A]
+            interface B {};
+            [Exposed=Window]
+            interface A {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow [LegacyWindowAlias] to conflict with other identifiers"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [Global, Exposed=Window] interface Window {};
+            [Exposed=Window, LegacyWindowAlias=A]
+            interface B {};
+            [Exposed=Window, LegacyWindowAlias=A]
+            interface C {};
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow [LegacyWindowAlias] to conflict with other identifiers"
+    )
diff --git a/dom/bindings/parser/tests/test_interface_const_identifier_conflicts.py b/dom/bindings/parser/tests/test_interface_const_identifier_conflicts.py
new file mode 100644
index 0000000000..84f9eeb1f4
--- /dev/null
+++ b/dom/bindings/parser/tests/test_interface_const_identifier_conflicts.py
@@ -0,0 +1,20 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflict {
+              const byte thing1 = 1;
+              const unsigned long thing1 = 1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_interface_identifier_conflicts_across_members.py b/dom/bindings/parser/tests/test_interface_identifier_conflicts_across_members.py
new file mode 100644
index 0000000000..32c0b24704
--- /dev/null
+++ b/dom/bindings/parser/tests/test_interface_identifier_conflicts_across_members.py
@@ -0,0 +1,171 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers1 {
+              const byte thing1 = 1;
+              readonly attribute long thing1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers1.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers2 {
+              readonly attribute long thing1;
+              const byte thing1 = 1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers2.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers3 {
+              getter boolean thing1(DOMString name);
+              readonly attribute long thing1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers3.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers4 {
+              const byte thing1 = 1;
+              long thing1();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers4.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers5 {
+              static long thing1();
+              undefined thing1();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        not threw, "Should not have thrown for IdentifierConflictAcrossMembers5."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin IdentifierConflictAcrossMembers6Mixin {
+              undefined thing1();
+            };
+            interface IdentifierConflictAcrossMembers6 {
+              static long thing1();
+            };
+            IdentifierConflictAcrossMembers6 includes IdentifierConflictAcrossMembers6Mixin;
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        not threw, "Should not have thrown for IdentifierConflictAcrossMembers6."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers7 {
+              const byte thing1 = 1;
+              static readonly attribute long thing1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers7.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers8 {
+              readonly attribute long thing1 = 1;
+              static readonly attribute long thing1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers8.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IdentifierConflictAcrossMembers9 {
+              void thing1();
+              static readonly attribute long thing1;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for IdentifierConflictAcrossMembers9.")
diff --git a/dom/bindings/parser/tests/test_interface_maplikesetlikeiterable.py b/dom/bindings/parser/tests/test_interface_maplikesetlikeiterable.py
new file mode 100644
index 0000000000..fdd9c00965
--- /dev/null
+++ b/dom/bindings/parser/tests/test_interface_maplikesetlikeiterable.py
@@ -0,0 +1,935 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    def shouldPass(prefix, iface, expectedMembers, numProductions=1):
+        p = parser.reset()
+        p.parse(iface)
+        results = p.finish()
+        harness.check(
+            len(results),
+            numProductions,
+            "%s - Should have production count %d" % (prefix, numProductions),
+        )
+        harness.ok(
+            isinstance(results[0], WebIDL.IDLInterface),
+            "%s - Should be an IDLInterface" % (prefix),
+        )
+        # Make a copy, since we plan to modify it
+        expectedMembers = list(expectedMembers)
+        for m in results[0].members:
+            name = m.identifier.name
+            if m.isMethod() and m.isStatic():
+                # None of the expected members are static methods, so ignore those.
+                harness.ok(True, "%s - %s - Should be a %s" % (prefix, name, type(m)))
+            elif (name, type(m)) in expectedMembers:
+                harness.ok(True, "%s - %s - Should be a %s" % (prefix, name, type(m)))
+                expectedMembers.remove((name, type(m)))
+            else:
+                harness.ok(
+                    False,
+                    "%s - %s - Unknown symbol of type %s" % (prefix, name, type(m)),
+                )
+        # A bit of a hoop because we can't generate the error string if we pass
+        if len(expectedMembers) == 0:
+            harness.ok(True, "Found all the members")
+        else:
+            harness.ok(
+                False,
+                "Expected member not found: %s of type %s"
+                % (expectedMembers[0][0], expectedMembers[0][1]),
+            )
+        return results
+
+    def shouldFail(prefix, iface):
+        try:
+            p = parser.reset()
+            p.parse(iface)
+            p.finish()
+            harness.ok(False, prefix + " - Interface passed when should've failed")
+        except WebIDL.WebIDLError:
+            harness.ok(True, prefix + " - Interface failed as expected")
+        except Exception as e:
+            harness.ok(
+                False,
+                prefix
+                + " - Interface failed but not as a WebIDLError exception: %s" % e,
+            )
+
+    iterableMembers = [
+        (x, WebIDL.IDLMethod) for x in ["entries", "keys", "values", "forEach"]
+    ]
+    setROMembers = (
+        [(x, WebIDL.IDLMethod) for x in ["has"]]
+        + [("__setlike", WebIDL.IDLMaplikeOrSetlike)]
+        + iterableMembers
+    )
+    setROMembers.extend([("size", WebIDL.IDLAttribute)])
+    setRWMembers = [
+        (x, WebIDL.IDLMethod) for x in ["add", "clear", "delete"]
+    ] + setROMembers
+    mapROMembers = (
+        [(x, WebIDL.IDLMethod) for x in ["get", "has"]]
+        + [("__maplike", WebIDL.IDLMaplikeOrSetlike)]
+        + iterableMembers
+    )
+    mapROMembers.extend([("size", WebIDL.IDLAttribute)])
+    mapRWMembers = [
+        (x, WebIDL.IDLMethod) for x in ["set", "clear", "delete"]
+    ] + mapROMembers
+
+    # OK, now that we've used iterableMembers to set up the above, append
+    # __iterable to it for the iterable<> case.
+    iterableMembers.append(("__iterable", WebIDL.IDLIterable))
+
+    asyncIterableMembers = [
+        (x, WebIDL.IDLMethod) for x in ["entries", "keys", "values"]
+    ]
+    asyncIterableMembers.append(("__iterable", WebIDL.IDLAsyncIterable))
+
+    valueIterableMembers = [("__iterable", WebIDL.IDLIterable)]
+    valueIterableMembers.append(("__indexedgetter", WebIDL.IDLMethod))
+    valueIterableMembers.append(("length", WebIDL.IDLAttribute))
+
+    valueAsyncIterableMembers = [("__iterable", WebIDL.IDLAsyncIterable)]
+    valueAsyncIterableMembers.append(("values", WebIDL.IDLMethod))
+
+    disallowedIterableNames = [
+        ("keys", WebIDL.IDLMethod),
+        ("entries", WebIDL.IDLMethod),
+        ("values", WebIDL.IDLMethod),
+    ]
+    disallowedMemberNames = [
+        ("forEach", WebIDL.IDLMethod),
+        ("has", WebIDL.IDLMethod),
+        ("size", WebIDL.IDLAttribute),
+    ] + disallowedIterableNames
+    mapDisallowedMemberNames = [("get", WebIDL.IDLMethod)] + disallowedMemberNames
+    disallowedNonMethodNames = [
+        ("clear", WebIDL.IDLMethod),
+        ("delete", WebIDL.IDLMethod),
+    ]
+    mapDisallowedNonMethodNames = [("set", WebIDL.IDLMethod)] + disallowedNonMethodNames
+    setDisallowedNonMethodNames = [("add", WebIDL.IDLMethod)] + disallowedNonMethodNames
+    unrelatedMembers = [
+        ("unrelatedAttribute", WebIDL.IDLAttribute),
+        ("unrelatedMethod", WebIDL.IDLMethod),
+    ]
+
+    #
+    # Simple Usage Tests
+    #
+
+    shouldPass(
+        "Iterable (key only)",
+        """
+               interface Foo1 {
+               iterable<long>;
+               readonly attribute unsigned long length;
+               getter long(unsigned long index);
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        valueIterableMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Iterable (key only) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               iterable<long>;
+               readonly attribute unsigned long length;
+               getter long(unsigned long index);
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        valueIterableMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Iterable (key and value)",
+        """
+               interface Foo1 {
+               iterable<long, long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        iterableMembers + unrelatedMembers,
+        # numProductions == 2 because of the generated iterator iface,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Iterable (key and value) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               iterable<long, long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        iterableMembers,
+        # numProductions == 3 because of the generated iterator iface,
+        numProductions=3,
+    )
+
+    shouldPass(
+        "Async iterable (key only)",
+        """
+               interface Foo1 {
+               async iterable<long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        valueAsyncIterableMembers + unrelatedMembers,
+        # numProductions == 2 because of the generated iterator iface,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Async iterable (key only) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               async iterable<long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        valueAsyncIterableMembers,
+        # numProductions == 3 because of the generated iterator iface,
+        numProductions=3,
+    )
+
+    shouldPass(
+        "Async iterable with argument (key only)",
+        """
+               interface Foo1 {
+               async iterable<long>(optional long foo);
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        valueAsyncIterableMembers + unrelatedMembers,
+        # numProductions == 2 because of the generated iterator iface,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Async iterable (key and value)",
+        """
+               interface Foo1 {
+               async iterable<long, long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        asyncIterableMembers + unrelatedMembers,
+        # numProductions == 2 because of the generated iterator iface,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Async iterable (key and value) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               async iterable<long, long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        asyncIterableMembers,
+        # numProductions == 3 because of the generated iterator iface,
+        numProductions=3,
+    )
+
+    shouldPass(
+        "Async iterable with argument (key and value)",
+        """
+               interface Foo1 {
+               async iterable<long, long>(optional long foo);
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        asyncIterableMembers + unrelatedMembers,
+        # numProductions == 2 because of the generated iterator iface,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Maplike (readwrite)",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapRWMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Maplike (readwrite) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               maplike<long, long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Maplike (readwrite)",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapRWMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Maplike (readwrite) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               maplike<long, long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Maplike (readonly)",
+        """
+               interface Foo1 {
+               readonly maplike<long, long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapROMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Maplike (readonly) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               readonly maplike<long, long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        mapROMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Setlike (readwrite)",
+        """
+               interface Foo1 {
+               setlike<long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        setRWMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Setlike (readwrite) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               setlike<long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        setRWMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Setlike (readonly)",
+        """
+               interface Foo1 {
+               readonly setlike<long>;
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        setROMembers + unrelatedMembers,
+    )
+
+    shouldPass(
+        "Setlike (readonly) inheriting from parent",
+        """
+               interface Foo1 : Foo2 {
+               readonly setlike<long>;
+               };
+               interface Foo2 {
+               attribute long unrelatedAttribute;
+               long unrelatedMethod();
+               };
+               """,
+        setROMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Inheritance of maplike/setlike",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldFail(
+        "JS Implemented maplike interface",
+        """
+               [JSImplementation="@mozilla.org/dom/test-interface-js-maplike;1"]
+               interface Foo1 {
+               constructor();
+               setlike<long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "JS Implemented maplike interface",
+        """
+               [JSImplementation="@mozilla.org/dom/test-interface-js-maplike;1"]
+               interface Foo1 {
+               constructor();
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    #
+    # Multiple maplike/setlike tests
+    #
+
+    shouldFail(
+        "Two maplike/setlikes on same interface",
+        """
+               interface Foo1 {
+               setlike<long>;
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Two iterable/setlikes on same interface",
+        """
+               interface Foo1 {
+               iterable<long>;
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Two iterables on same interface",
+        """
+               interface Foo1 {
+               iterable<long>;
+               iterable<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Two iterables on same interface",
+        """
+               interface Foo1 {
+               iterable<long>;
+               async iterable<long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Two iterables on same interface",
+        """
+               interface Foo1 {
+               async iterable<long>;
+               async iterable<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Async iterable with non-optional arguments",
+        """
+               interface Foo1 {
+               async iterable<long>(long foo);
+               };
+               """,
+    )
+
+    shouldFail(
+        "Async iterable with non-optional arguments",
+        """
+               interface Foo1 {
+               async iterable<long>(optional long foo, long bar);
+               };
+               """,
+    )
+
+    shouldFail(
+        "Async iterable with non-optional arguments",
+        """
+               interface Foo1 {
+               async iterable<long, long>(long foo);
+               };
+               """,
+    )
+
+    shouldFail(
+        "Two maplike/setlikes in partials",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               partial interface Foo1 {
+               setlike<long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Conflicting maplike/setlikes across inheritance",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               setlike<long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Conflicting maplike/iterable across inheritance",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               iterable<long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Conflicting maplike/setlikes across multistep inheritance",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               setlike<long>;
+               };
+               """,
+    )
+
+    #
+    # Member name collision tests
+    #
+
+    def testConflictingMembers(
+        likeMember, conflict, expectedMembers, methodPasses, numProductions=1
+    ):
+        """
+        Tests for maplike/setlike member generation against conflicting member
+        names. If methodPasses is True, this means we expect the interface to
+        pass in the case of method shadowing, and expectedMembers should be the
+        list of interface members to check against on the passing interface.
+
+        """
+        (conflictName, conflictType) = conflict
+        if methodPasses:
+            shouldPass(
+                "Conflicting method: %s and %s" % (likeMember, conflictName),
+                """
+                       interface Foo1 {
+                       %s;
+                       [Throws]
+                       undefined %s(long test1, double test2, double test3);
+                       };
+                       """
+                % (likeMember, conflictName),
+                expectedMembers,
+            )
+        else:
+            shouldFail(
+                "Conflicting method: %s and %s" % (likeMember, conflictName),
+                """
+                       interface Foo1 {
+                       %s;
+                       [Throws]
+                       undefined %s(long test1, double test2, double test3);
+                       };
+                       """
+                % (likeMember, conflictName),
+            )
+        # Inherited conflicting methods should ALWAYS fail
+        shouldFail(
+            "Conflicting inherited method: %s and %s" % (likeMember, conflictName),
+            """
+                   interface Foo1 {
+                   undefined %s(long test1, double test2, double test3);
+                   };
+                   interface Foo2 : Foo1 {
+                   %s;
+                   };
+                   """
+            % (conflictName, likeMember),
+        )
+        if conflictType == WebIDL.IDLAttribute:
+            shouldFail(
+                "Conflicting static method: %s and %s" % (likeMember, conflictName),
+                """
+                       interface Foo1 {
+                       %s;
+                       static undefined %s(long test1, double test2, double test3);
+                       };
+                       """
+                % (likeMember, conflictName),
+            )
+        else:
+            shouldPass(
+                "Conflicting static method: %s and %s" % (likeMember, conflictName),
+                """
+                       interface Foo1 {
+                       %s;
+                       static undefined %s(long test1, double test2, double test3);
+                       };
+                       """
+                % (likeMember, conflictName),
+                expectedMembers,
+                numProductions=numProductions,
+            )
+        shouldFail(
+            "Conflicting attribute: %s and %s" % (likeMember, conflictName),
+            """
+                   interface Foo1 {
+                   %s
+                   attribute double %s;
+                   };
+                   """
+            % (likeMember, conflictName),
+        )
+        shouldFail(
+            "Conflicting const: %s and %s" % (likeMember, conflictName),
+            """
+                   interface Foo1 {
+                   %s;
+                   const double %s = 0;
+                   };
+                   """
+            % (likeMember, conflictName),
+        )
+        shouldFail(
+            "Conflicting static attribute: %s and %s" % (likeMember, conflictName),
+            """
+                   interface Foo1 {
+                   %s;
+                   static attribute long %s;
+                   };
+                   """
+            % (likeMember, conflictName),
+        )
+
+    for member in disallowedIterableNames:
+        testConflictingMembers(
+            "iterable<long, long>", member, iterableMembers, False, numProductions=2
+        )
+    for member in mapDisallowedMemberNames:
+        testConflictingMembers("maplike<long, long>", member, mapRWMembers, False)
+    for member in disallowedMemberNames:
+        testConflictingMembers("setlike<long>", member, setRWMembers, False)
+    for member in mapDisallowedNonMethodNames:
+        testConflictingMembers("maplike<long, long>", member, mapRWMembers, True)
+    for member in setDisallowedNonMethodNames:
+        testConflictingMembers("setlike<long>", member, setRWMembers, True)
+
+    shouldPass(
+        "Inheritance of maplike/setlike with child member collision",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               undefined entries();
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Inheritance of multi-level maplike/setlike with child member collision",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               undefined entries();
+               };
+               """,
+        mapRWMembers,
+        numProductions=3,
+    )
+
+    shouldFail(
+        "Maplike interface with mixin member collision",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface mixin Foo2 {
+               undefined entries();
+               };
+               Foo1 includes Foo2;
+               """,
+    )
+
+    shouldPass(
+        "Inherited Maplike interface with consequential interface member collision",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface mixin Foo2 {
+               undefined entries();
+               };
+               interface Foo3 : Foo1 {
+               };
+               Foo3 includes Foo2;
+               """,
+        mapRWMembers,
+        numProductions=4,
+    )
+
+    shouldFail(
+        "Inheritance of name collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               undefined entries();
+               };
+               interface Foo2 : Foo1 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Inheritance of multi-level name collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               undefined entries();
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldPass(
+        "Inheritance of attribute collision with parent maplike/setlike",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               attribute double size;
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldPass(
+        "Inheritance of multi-level attribute collision with parent maplike/setlike",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               attribute double size;
+               };
+               """,
+        mapRWMembers,
+        numProductions=3,
+    )
+
+    shouldFail(
+        "Inheritance of attribute collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               attribute double size;
+               };
+               interface Foo2 : Foo1 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Inheritance of multi-level attribute collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               attribute double size;
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Inheritance of attribute/rw function collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               attribute double set;
+               };
+               interface Foo2 : Foo1 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Inheritance of const/rw function collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               const double set = 0;
+               };
+               interface Foo2 : Foo1 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldPass(
+        "Inheritance of rw function with same name in child maplike/setlike",
+        """
+               interface Foo1 {
+               maplike<long, long>;
+               };
+               interface Foo2 : Foo1 {
+               undefined clear();
+               };
+               """,
+        mapRWMembers,
+        numProductions=2,
+    )
+
+    shouldFail(
+        "Inheritance of unforgeable attribute collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               [LegacyUnforgeable]
+               attribute double size;
+               };
+               interface Foo2 : Foo1 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldFail(
+        "Inheritance of multi-level unforgeable attribute collision with child maplike/setlike",
+        """
+               interface Foo1 {
+               [LegacyUnforgeable]
+               attribute double size;
+               };
+               interface Foo2 : Foo1 {
+               };
+               interface Foo3 : Foo2 {
+               maplike<long, long>;
+               };
+               """,
+    )
+
+    shouldPass(
+        "Interface with readonly allowable overrides",
+        """
+               interface Foo1 {
+               readonly setlike<long>;
+               readonly attribute boolean clear;
+               };
+               """,
+        setROMembers + [("clear", WebIDL.IDLAttribute)],
+    )
+
+    r = shouldPass(
+        "Check proper override of clear/delete/set",
+        """
+                   interface Foo1 {
+                   maplike<long, long>;
+                   long clear(long a, long b, double c, double d);
+                   long set(long a, long b, double c, double d);
+                   long delete(long a, long b, double c, double d);
+                   };
+                   """,
+        mapRWMembers,
+    )
+
+    for m in r[0].members:
+        if m.identifier.name in ["clear", "set", "delete"]:
+            harness.ok(m.isMethod(), "%s should be a method" % m.identifier.name)
+            harness.check(
+                m.maxArgCount, 4, "%s should have 4 arguments" % m.identifier.name
+            )
+            harness.ok(
+                not m.isMaplikeOrSetlikeOrIterableMethod(),
+                "%s should not be a maplike/setlike function" % m.identifier.name,
+            )
diff --git a/dom/bindings/parser/tests/test_interfacemixin.py b/dom/bindings/parser/tests/test_interfacemixin.py
new file mode 100644
index 0000000000..66eae58091
--- /dev/null
+++ b/dom/bindings/parser/tests/test_interfacemixin.py
@@ -0,0 +1,534 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse("interface mixin Foo { };")
+    results = parser.finish()
+    harness.ok(True, "Empty interface mixin parsed without error.")
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(
+        isinstance(results[0], WebIDL.IDLInterfaceMixin),
+        "Should be an IDLInterfaceMixin",
+    )
+    mixin = results[0]
+    harness.check(
+        mixin.identifier.QName(), "::Foo", "Interface mixin has the right QName"
+    )
+    harness.check(mixin.identifier.name, "Foo", "Interface mixin has the right name")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface mixin QNameBase {
+            const long foo = 3;
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(len(results), 1, "Should be one productions")
+    harness.ok(
+        isinstance(results[0], WebIDL.IDLInterfaceMixin),
+        "Should be an IDLInterfaceMixin",
+    )
+    harness.check(len(results[0].members), 1, "Expect 1 productions")
+    mixin = results[0]
+    harness.check(
+        mixin.members[0].identifier.QName(),
+        "::QNameBase::foo",
+        "Member has the right QName",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface mixin A {
+            readonly attribute boolean x;
+            undefined foo();
+        };
+        partial interface mixin A {
+            readonly attribute boolean y;
+            undefined foo(long arg);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results), 2, "Should have two results with partial interface mixin"
+    )
+    mixin = results[0]
+    harness.check(
+        len(mixin.members), 3, "Should have three members with partial interface mixin"
+    )
+    harness.check(
+        mixin.members[0].identifier.name,
+        "x",
+        "First member should be x with partial interface mixin",
+    )
+    harness.check(
+        mixin.members[1].identifier.name,
+        "foo",
+        "Second member should be foo with partial interface mixin",
+    )
+    harness.check(
+        len(mixin.members[1].signatures()),
+        2,
+        "Should have two foo signatures with partial interface mixin",
+    )
+    harness.check(
+        mixin.members[2].identifier.name,
+        "y",
+        "Third member should be y with partial interface mixin",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        partial interface mixin A {
+            readonly attribute boolean y;
+            undefined foo(long arg);
+        };
+        interface mixin A {
+            readonly attribute boolean x;
+            undefined foo();
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results), 2, "Should have two results with reversed partial interface mixin"
+    )
+    mixin = results[1]
+    harness.check(
+        len(mixin.members),
+        3,
+        "Should have three members with reversed partial interface mixin",
+    )
+    harness.check(
+        mixin.members[0].identifier.name,
+        "x",
+        "First member should be x with reversed partial interface mixin",
+    )
+    harness.check(
+        mixin.members[1].identifier.name,
+        "foo",
+        "Second member should be foo with reversed partial interface mixin",
+    )
+    harness.check(
+        len(mixin.members[1].signatures()),
+        2,
+        "Should have two foo signatures with reversed partial interface mixin",
+    )
+    harness.check(
+        mixin.members[2].identifier.name,
+        "y",
+        "Third member should be y with reversed partial interface mixin",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface Interface {};
+        interface mixin Mixin {
+            attribute short x;
+        };
+        Interface includes Mixin;
+    """
+    )
+    results = parser.finish()
+    iface = results[0]
+    harness.check(len(iface.members), 1, "Should merge members from mixins")
+    harness.check(
+        iface.members[0].identifier.name, "x", "Should merge members from mixins"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                readonly attribute boolean x;
+            };
+            interface mixin A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow two non-partial interface mixins with the same name"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            partial interface mixin A {
+                readonly attribute boolean x;
+            };
+            partial interface mixin A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Must have a non-partial interface mixin for a given name")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+                boolean x;
+            };
+            partial interface mixin A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between partial interface "
+        "mixin and other object",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary A {
+                boolean x;
+            };
+            interface mixin A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between interface mixin " "and other object",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                readonly attribute boolean x;
+            };
+            interface A;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a name collision between external interface "
+        "and interface mixin",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SomeRandomAnnotation]
+            interface mixin A {
+                readonly attribute boolean y;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow unknown extended attributes on interface mixins"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                getter double (DOMString propertyName);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow getters on interface mixins")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                setter undefined (DOMString propertyName, double propertyValue);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow setters on interface mixins")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                deleter undefined (DOMString propertyName);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow deleters on interface mixins")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                legacycaller double compute(double x);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow legacycallers on interface mixins")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin A {
+                inherit attribute x;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow inherited attribute on interface mixins")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Interface {};
+            interface NotMixin {
+                attribute short x;
+            };
+            Interface includes NotMixin;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should fail if the right side does not point an interface mixin")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin NotInterface {};
+            interface mixin Mixin {
+                attribute short x;
+            };
+            NotInterface includes Mixin;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should fail if the left side does not point an interface")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin Mixin {
+                iterable<DOMString>;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should fail if an interface mixin includes iterable")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin Mixin {
+                setlike<DOMString>;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should fail if an interface mixin includes setlike")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface mixin Mixin {
+                maplike<DOMString, DOMString>;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should fail if an interface mixin includes maplike")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Interface {
+                attribute short attr;
+            };
+            interface mixin Mixin {
+                attribute short attr;
+            };
+            Interface includes Mixin;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should fail if the included mixin interface has duplicated member"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Interface {};
+            interface mixin Mixin1 {
+                attribute short attr;
+            };
+            interface mixin Mixin2 {
+                attribute short attr;
+            };
+            Interface includes Mixin1;
+            Interface includes Mixin2;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should fail if the included mixin interfaces have duplicated member"
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Window] interface Window {};
+        [Global, Exposed=Worker] interface Worker {};
+        [Exposed=Window]
+        interface Base {};
+        interface mixin Mixin {
+            Base returnSelf();
+        };
+        Base includes Mixin;
+    """
+    )
+    results = parser.finish()
+    base = results[2]
+    attr = base.members[0]
+    harness.check(
+        attr.exposureSet,
+        set(["Window"]),
+        "Should expose on globals where the base interfaces are exposed",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Window] interface Window {};
+        [Global, Exposed=Worker] interface Worker {};
+        [Exposed=Window]
+        interface Base {};
+        [Exposed=Window]
+        interface mixin Mixin {
+            attribute short a;
+        };
+        Base includes Mixin;
+    """
+    )
+    results = parser.finish()
+    base = results[2]
+    attr = base.members[0]
+    harness.check(
+        attr.exposureSet, set(["Window"]), "Should follow [Exposed] on interface mixin"
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        [Global, Exposed=Window] interface Window {};
+        [Global, Exposed=Worker] interface Worker {};
+        [Exposed=Window]
+        interface Base1 {};
+        [Exposed=Worker]
+        interface Base2 {};
+        interface mixin Mixin {
+            attribute short a;
+        };
+        Base1 includes Mixin;
+        Base2 includes Mixin;
+    """
+    )
+    results = parser.finish()
+    base = results[2]
+    attr = base.members[0]
+    harness.check(
+        attr.exposureSet,
+        set(["Window", "Worker"]),
+        "Should expose on all globals where including interfaces are " "exposed",
+    )
+    base = results[3]
+    attr = base.members[0]
+    harness.check(
+        attr.exposureSet,
+        set(["Window", "Worker"]),
+        "Should expose on all globals where including interfaces are " "exposed",
+    )
diff --git a/dom/bindings/parser/tests/test_lenientSetter.py b/dom/bindings/parser/tests/test_lenientSetter.py
new file mode 100644
index 0000000000..9059255594
--- /dev/null
+++ b/dom/bindings/parser/tests/test_lenientSetter.py
@@ -0,0 +1,86 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import WebIDL
+
+
+def should_throw(parser, harness, message, code):
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(code)
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown: %s" % message)
+
+
+def WebIDLTest(parser, harness):
+    # The [LegacyLenientSetter] extended attribute MUST take no arguments.
+    should_throw(
+        parser,
+        harness,
+        "no arguments",
+        """
+        interface I {
+          [LegacyLenientSetter=X] readonly attribute long A;
+        };
+    """,
+    )
+
+    # An attribute with the [LegacyLenientSetter] extended attribute MUST NOT
+    # also be declared with the [PutForwards] extended attribute.
+    should_throw(
+        parser,
+        harness,
+        "PutForwards",
+        """
+        interface I {
+          [PutForwards=B, LegacyLenientSetter] readonly attribute J A;
+        };
+        interface J {
+          attribute long B;
+        };
+    """,
+    )
+
+    # An attribute with the [LegacyLenientSetter] extended attribute MUST NOT
+    # also be declared with the [Replaceable] extended attribute.
+    should_throw(
+        parser,
+        harness,
+        "Replaceable",
+        """
+        interface I {
+          [Replaceable, LegacyLenientSetter] readonly attribute J A;
+        };
+    """,
+    )
+
+    # The [LegacyLenientSetter] extended attribute MUST NOT be used on an
+    # attribute that is not read only.
+    should_throw(
+        parser,
+        harness,
+        "writable attribute",
+        """
+        interface I {
+          [LegacyLenientSetter] attribute long A;
+        };
+    """,
+    )
+
+    # The [LegacyLenientSetter] extended attribute MUST NOT be used on a
+    # static attribute.
+    should_throw(
+        parser,
+        harness,
+        "static attribute",
+        """
+        interface I {
+          [LegacyLenientSetter] static readonly attribute long A;
+        };
+    """,
+    )
diff --git a/dom/bindings/parser/tests/test_method.py b/dom/bindings/parser/tests/test_method.py
new file mode 100644
index 0000000000..80eb004372
--- /dev/null
+++ b/dom/bindings/parser/tests/test_method.py
@@ -0,0 +1,430 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestMethods {
+          undefined basic();
+          static undefined basicStatic();
+          undefined basicWithSimpleArgs(boolean arg1, byte arg2, unsigned long arg3);
+          boolean basicBoolean();
+          static boolean basicStaticBoolean();
+          boolean basicBooleanWithSimpleArgs(boolean arg1, byte arg2, unsigned long arg3);
+          undefined optionalArg(optional byte? arg1, optional sequence<byte> arg2);
+          undefined variadicArg(byte?... arg1);
+          object getObject();
+          undefined setObject(object arg1);
+          undefined setAny(any arg1);
+          float doFloats(float arg1);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestMethods interface parsed without error.")
+    harness.check(len(results), 1, "Should be one production.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestMethods", "Interface has the right QName"
+    )
+    harness.check(iface.identifier.name, "TestMethods", "Interface has the right name")
+    harness.check(len(iface.members), 12, "Expect 12 members")
+
+    methods = iface.members
+
+    def checkArgument(argument, QName, name, type, optional, variadic):
+        harness.ok(isinstance(argument, WebIDL.IDLArgument), "Should be an IDLArgument")
+        harness.check(
+            argument.identifier.QName(), QName, "Argument has the right QName"
+        )
+        harness.check(argument.identifier.name, name, "Argument has the right name")
+        harness.check(str(argument.type), type, "Argument has the right return type")
+        harness.check(
+            argument.optional, optional, "Argument has the right optional value"
+        )
+        harness.check(
+            argument.variadic, variadic, "Argument has the right variadic value"
+        )
+
+    def checkMethod(
+        method,
+        QName,
+        name,
+        signatures,
+        static=False,
+        getter=False,
+        setter=False,
+        deleter=False,
+        legacycaller=False,
+        stringifier=False,
+    ):
+        harness.ok(isinstance(method, WebIDL.IDLMethod), "Should be an IDLMethod")
+        harness.ok(method.isMethod(), "Method is a method")
+        harness.ok(not method.isAttr(), "Method is not an attr")
+        harness.ok(not method.isConst(), "Method is not a const")
+        harness.check(method.identifier.QName(), QName, "Method has the right QName")
+        harness.check(method.identifier.name, name, "Method has the right name")
+        harness.check(method.isStatic(), static, "Method has the correct static value")
+        harness.check(method.isGetter(), getter, "Method has the correct getter value")
+        harness.check(method.isSetter(), setter, "Method has the correct setter value")
+        harness.check(
+            method.isDeleter(), deleter, "Method has the correct deleter value"
+        )
+        harness.check(
+            method.isLegacycaller(),
+            legacycaller,
+            "Method has the correct legacycaller value",
+        )
+        harness.check(
+            method.isStringifier(),
+            stringifier,
+            "Method has the correct stringifier value",
+        )
+        harness.check(
+            len(method.signatures()),
+            len(signatures),
+            "Method has the correct number of signatures",
+        )
+
+        sigpairs = zip(method.signatures(), signatures)
+        for gotSignature, expectedSignature in sigpairs:
+            (gotRetType, gotArgs) = gotSignature
+            (expectedRetType, expectedArgs) = expectedSignature
+
+            harness.check(
+                str(gotRetType), expectedRetType, "Method has the expected return type."
+            )
+
+            for i in range(0, len(gotArgs)):
+                (QName, name, type, optional, variadic) = expectedArgs[i]
+                checkArgument(gotArgs[i], QName, name, type, optional, variadic)
+
+    checkMethod(methods[0], "::TestMethods::basic", "basic", [("Undefined", [])])
+    checkMethod(
+        methods[1],
+        "::TestMethods::basicStatic",
+        "basicStatic",
+        [("Undefined", [])],
+        static=True,
+    )
+    checkMethod(
+        methods[2],
+        "::TestMethods::basicWithSimpleArgs",
+        "basicWithSimpleArgs",
+        [
+            (
+                "Undefined",
+                [
+                    (
+                        "::TestMethods::basicWithSimpleArgs::arg1",
+                        "arg1",
+                        "Boolean",
+                        False,
+                        False,
+                    ),
+                    (
+                        "::TestMethods::basicWithSimpleArgs::arg2",
+                        "arg2",
+                        "Byte",
+                        False,
+                        False,
+                    ),
+                    (
+                        "::TestMethods::basicWithSimpleArgs::arg3",
+                        "arg3",
+                        "UnsignedLong",
+                        False,
+                        False,
+                    ),
+                ],
+            )
+        ],
+    )
+    checkMethod(
+        methods[3], "::TestMethods::basicBoolean", "basicBoolean", [("Boolean", [])]
+    )
+    checkMethod(
+        methods[4],
+        "::TestMethods::basicStaticBoolean",
+        "basicStaticBoolean",
+        [("Boolean", [])],
+        static=True,
+    )
+    checkMethod(
+        methods[5],
+        "::TestMethods::basicBooleanWithSimpleArgs",
+        "basicBooleanWithSimpleArgs",
+        [
+            (
+                "Boolean",
+                [
+                    (
+                        "::TestMethods::basicBooleanWithSimpleArgs::arg1",
+                        "arg1",
+                        "Boolean",
+                        False,
+                        False,
+                    ),
+                    (
+                        "::TestMethods::basicBooleanWithSimpleArgs::arg2",
+                        "arg2",
+                        "Byte",
+                        False,
+                        False,
+                    ),
+                    (
+                        "::TestMethods::basicBooleanWithSimpleArgs::arg3",
+                        "arg3",
+                        "UnsignedLong",
+                        False,
+                        False,
+                    ),
+                ],
+            )
+        ],
+    )
+    checkMethod(
+        methods[6],
+        "::TestMethods::optionalArg",
+        "optionalArg",
+        [
+            (
+                "Undefined",
+                [
+                    (
+                        "::TestMethods::optionalArg::arg1",
+                        "arg1",
+                        "ByteOrNull",
+                        True,
+                        False,
+                    ),
+                    (
+                        "::TestMethods::optionalArg::arg2",
+                        "arg2",
+                        "ByteSequence",
+                        True,
+                        False,
+                    ),
+                ],
+            )
+        ],
+    )
+    checkMethod(
+        methods[7],
+        "::TestMethods::variadicArg",
+        "variadicArg",
+        [
+            (
+                "Undefined",
+                [
+                    (
+                        "::TestMethods::variadicArg::arg1",
+                        "arg1",
+                        "ByteOrNull",
+                        True,
+                        True,
+                    )
+                ],
+            )
+        ],
+    )
+    checkMethod(methods[8], "::TestMethods::getObject", "getObject", [("Object", [])])
+    checkMethod(
+        methods[9],
+        "::TestMethods::setObject",
+        "setObject",
+        [
+            (
+                "Undefined",
+                [("::TestMethods::setObject::arg1", "arg1", "Object", False, False)],
+            )
+        ],
+    )
+    checkMethod(
+        methods[10],
+        "::TestMethods::setAny",
+        "setAny",
+        [("Undefined", [("::TestMethods::setAny::arg1", "arg1", "Any", False, False)])],
+    )
+    checkMethod(
+        methods[11],
+        "::TestMethods::doFloats",
+        "doFloats",
+        [("Float", [("::TestMethods::doFloats::arg1", "arg1", "Float", False, False)])],
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            undefined foo(optional float bar = 1);
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow integer to float type corecion")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [GetterThrows] undefined foo();
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [GetterThrows] on methods")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [SetterThrows] undefined foo();
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [SetterThrows] on methods")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throw] undefined foo();
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should spell [Throws] correctly on methods")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            undefined __noSuchMethod__();
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow __noSuchMethod__ methods")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throws, LenientFloat]
+            undefined foo(float myFloat);
+            [Throws]
+            undefined foo();
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow LenientFloat to be only in a specific overload")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      interface A {
+        [Throws]
+        undefined foo();
+        [Throws, LenientFloat]
+        undefined foo(float myFloat);
+      };
+    """
+    )
+    results = parser.finish()
+    iface = results[0]
+    methods = iface.members
+    lenientFloat = methods[0].getExtendedAttribute("LenientFloat")
+    harness.ok(
+        lenientFloat is not None,
+        "LenientFloat in overloads must be added to the method",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throws, LenientFloat]
+            undefined foo(float myFloat);
+            [Throws]
+            undefined foo(float myFloat, float yourFloat);
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should prevent overloads from getting different restricted float behavior",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throws]
+            undefined foo(float myFloat, float yourFloat);
+            [Throws, LenientFloat]
+            undefined foo(float myFloat);
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should prevent overloads from getting different restricted float behavior (2)",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface A {
+            [Throws, LenientFloat]
+            undefined foo(float myFloat);
+            [Throws, LenientFloat]
+            undefined foo(short myShort);
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should prevent overloads from getting redundant [LenientFloat]")
diff --git a/dom/bindings/parser/tests/test_namespace.py b/dom/bindings/parser/tests/test_namespace.py
new file mode 100644
index 0000000000..5812364ddd
--- /dev/null
+++ b/dom/bindings/parser/tests/test_namespace.py
@@ -0,0 +1,235 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        namespace MyNamespace {
+          attribute any foo;
+          any bar();
+        };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(len(results), 1, "Should have a thing.")
+    harness.ok(results[0].isNamespace(), "Our thing should be a namespace")
+    harness.check(len(results[0].members), 2, "Should have two things in our namespace")
+    harness.ok(results[0].members[0].isAttr(), "First member is attribute")
+    harness.ok(results[0].members[0].isStatic(), "Attribute should be static")
+    harness.ok(results[0].members[1].isMethod(), "Second member is method")
+    harness.ok(results[0].members[1].isStatic(), "Operation should be static")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        namespace MyNamespace {
+          attribute any foo;
+        };
+        partial namespace MyNamespace {
+          any bar();
+        };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(len(results), 2, "Should have things.")
+    harness.ok(results[0].isNamespace(), "Our thing should be a namespace")
+    harness.check(len(results[0].members), 2, "Should have two things in our namespace")
+    harness.ok(results[0].members[0].isAttr(), "First member is attribute")
+    harness.ok(results[0].members[0].isStatic(), "Attribute should be static")
+    harness.ok(results[0].members[1].isMethod(), "Second member is method")
+    harness.ok(results[0].members[1].isStatic(), "Operation should be static")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        partial namespace MyNamespace {
+          any bar();
+        };
+        namespace MyNamespace {
+          attribute any foo;
+        };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(len(results), 2, "Should have things.")
+    harness.ok(results[1].isNamespace(), "Our thing should be a namespace")
+    harness.check(len(results[1].members), 2, "Should have two things in our namespace")
+    harness.ok(results[1].members[0].isAttr(), "First member is attribute")
+    harness.ok(results[1].members[0].isStatic(), "Attribute should be static")
+    harness.ok(results[1].members[1].isMethod(), "Second member is method")
+    harness.ok(results[1].members[1].isStatic(), "Operation should be static")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            namespace MyNamespace {
+              static attribute any foo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            namespace MyNamespace {
+              static any bar();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            namespace MyNamespace {
+              any bar();
+            };
+
+            interface MyNamespace {
+              any baz();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface MyNamespace {
+              any baz();
+            };
+
+            namespace MyNamespace {
+              any bar();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            namespace MyNamespace {
+              any baz();
+            };
+
+            namespace MyNamespace {
+              any bar();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            partial namespace MyNamespace {
+              any baz();
+            };
+
+            interface MyNamespace {
+              any bar();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            namespace MyNamespace {
+              any bar();
+            };
+
+            partial interface MyNamespace {
+              any baz();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            partial interface MyNamespace {
+              any baz();
+            };
+
+            namespace MyNamespace {
+              any bar();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface MyNamespace {
+              any bar();
+            };
+
+            partial namespace MyNamespace {
+              any baz();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_newobject.py b/dom/bindings/parser/tests/test_newobject.py
new file mode 100644
index 0000000000..b30e9c5816
--- /dev/null
+++ b/dom/bindings/parser/tests/test_newobject.py
@@ -0,0 +1,76 @@
+import WebIDL
+
+
+# Import the WebIDL module, so we can do isinstance checks and whatnot
+def WebIDLTest(parser, harness):
+    # Basic functionality
+    parser.parse(
+        """
+        interface Iface {
+          [NewObject] readonly attribute Iface attr;
+          [NewObject] Iface method();
+        };
+        """
+    )
+    results = parser.finish()
+    harness.ok(results, "Should not have thrown on basic [NewObject] usage")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Pure, NewObject] readonly attribute Iface attr;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must depend on something")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Pure, NewObject] Iface method();
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[NewObject] methods must depend on something")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [Cached, NewObject, Affects=Nothing] readonly attribute Iface attr;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must not be [Cached]")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Iface {
+              [StoreInSlot, NewObject, Affects=Nothing] readonly attribute Iface attr;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[NewObject] attributes must not be [StoreInSlot]")
diff --git a/dom/bindings/parser/tests/test_nullable_equivalency.py b/dom/bindings/parser/tests/test_nullable_equivalency.py
new file mode 100644
index 0000000000..5790288ccb
--- /dev/null
+++ b/dom/bindings/parser/tests/test_nullable_equivalency.py
@@ -0,0 +1,145 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestNullableEquivalency1 {
+          attribute long  a;
+          attribute long? b;
+        };
+
+        interface TestNullableEquivalency2 {
+          attribute ArrayBuffer  a;
+          attribute ArrayBuffer? b;
+        };
+
+        /* Can't have dictionary-valued attributes, so can't test that here */
+
+        enum TestNullableEquivalency4Enum {
+          "Foo",
+          "Bar"
+        };
+
+        interface TestNullableEquivalency4 {
+          attribute TestNullableEquivalency4Enum  a;
+          attribute TestNullableEquivalency4Enum? b;
+        };
+
+        interface TestNullableEquivalency5 {
+          attribute TestNullableEquivalency4  a;
+          attribute TestNullableEquivalency4? b;
+        };
+
+        interface TestNullableEquivalency6 {
+          attribute boolean  a;
+          attribute boolean? b;
+        };
+
+        interface TestNullableEquivalency7 {
+          attribute DOMString  a;
+          attribute DOMString? b;
+        };
+
+        interface TestNullableEquivalency8 {
+          attribute float  a;
+          attribute float? b;
+        };
+
+        interface TestNullableEquivalency9 {
+          attribute double  a;
+          attribute double? b;
+        };
+
+        interface TestNullableEquivalency10 {
+          attribute object  a;
+          attribute object? b;
+        };
+    """
+    )
+
+    for decl in parser.finish():
+        if decl.isInterface():
+            checkEquivalent(decl, harness)
+
+
+def checkEquivalent(iface, harness):
+    type1 = iface.members[0].type
+    type2 = iface.members[1].type
+
+    harness.check(type1.nullable(), False, "attr1 should not be nullable")
+    harness.check(type2.nullable(), True, "attr2 should be nullable")
+
+    # We don't know about type1, but type2, the nullable type, definitely
+    # shouldn't be builtin.
+    harness.check(type2.builtin, False, "attr2 should not be builtin")
+
+    # Ensure that all attributes of type2 match those in type1, except for:
+    #  - names on an ignore list,
+    #  - names beginning with '_',
+    #  - functions which throw when called with no args, and
+    #  - class-level non-callables ("static variables").
+    #
+    # Yes, this is an ugly, fragile hack.  But it finds bugs...
+    for attr in dir(type1):
+        if (
+            attr.startswith("_")
+            or attr
+            in [
+                "nullable",
+                "builtin",
+                "filename",
+                "location",
+                "inner",
+                "QName",
+                "getDeps",
+                "name",
+                "prettyName",
+            ]
+            or (hasattr(type(type1), attr) and not callable(getattr(type1, attr)))
+        ):
+            continue
+
+        a1 = getattr(type1, attr)
+
+        if callable(a1):
+            try:
+                v1 = a1()
+            except AssertionError:
+                # Various methods assert that they're called on objects of
+                # the right type, skip them if the assert fails.
+                continue
+            except TypeError:
+                # a1 requires positional arguments, so skip this attribute.
+                continue
+
+            try:
+                a2 = getattr(type2, attr)
+            except WebIDL.WebIDLError:
+                harness.ok(
+                    False,
+                    "Missing %s attribute on type %s in %s" % (attr, type2, iface),
+                )
+                continue
+
+            if not callable(a2):
+                harness.ok(
+                    False,
+                    "%s attribute on type %s in %s wasn't callable"
+                    % (attr, type2, iface),
+                )
+                continue
+
+            v2 = a2()
+            harness.check(v2, v1, "%s method return value" % attr)
+        else:
+            try:
+                a2 = getattr(type2, attr)
+            except WebIDL.WebIDLError:
+                harness.ok(
+                    False,
+                    "Missing %s attribute on type %s in %s" % (attr, type2, iface),
+                )
+                continue
+
+            harness.check(a2, a1, "%s attribute should match" % attr)
diff --git a/dom/bindings/parser/tests/test_nullable_void.py b/dom/bindings/parser/tests/test_nullable_void.py
new file mode 100644
index 0000000000..f2a0177ced
--- /dev/null
+++ b/dom/bindings/parser/tests/test_nullable_void.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface NullableVoid {
+              void? foo();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_observableArray.py b/dom/bindings/parser/tests/test_observableArray.py
new file mode 100644
index 0000000000..7fe9511e07
--- /dev/null
+++ b/dom/bindings/parser/tests/test_observableArray.py
@@ -0,0 +1,287 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+def WebIDLTest(parser, harness):
+    # Test dictionary as inner type
+    harness.should_throw(
+        parser,
+        """
+        dictionary A {
+          boolean member;
+        };
+        interface B {
+          attribute ObservableArray<A> foo;
+        };
+        """,
+        "use dictionary as inner type",
+    )
+
+    # Test sequence as inner type
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          attribute ObservableArray<sequence<boolean>> foo;
+        };
+        """,
+        "use sequence as inner type",
+    )
+
+    # Test sequence<dictionary> as inner type
+    harness.should_throw(
+        parser,
+        """
+        dictionary A {
+            boolean member;
+        };
+        interface B {
+          attribute ObservableArray<sequence<A>> foo;
+        };
+        """,
+        "use sequence<dictionary> as inner type",
+    )
+
+    # Test record as inner type
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          attribute ObservableArray<record<DOMString, boolean>> foo;
+        };
+        """,
+        "use record as inner type",
+    )
+
+    # Test record<dictionary> as inner type
+    harness.should_throw(
+        parser,
+        """
+        dictionary A {
+            boolean member;
+        };
+        interface B {
+          attribute ObservableArray<record<DOMString, A>> foo;
+        };
+        """,
+        "use record<dictionary> as inner type",
+    )
+
+    # Test observable array as inner type
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          attribute ObservableArray<ObservableArray<boolean>> foo;
+        };
+        """,
+        "use ObservableArray as inner type",
+    )
+
+    # Test nullable attribute
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          attribute ObservableArray<boolean>? foo;
+        };
+        """,
+        "nullable",
+    )
+
+    # Test sequence
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          undefined foo(sequence<ObservableArray<boolean>> foo);
+        };
+        """,
+        "used in sequence",
+    )
+
+    # Test record
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          undefined foo(record<DOMString, ObservableArray<boolean>> foo);
+        };
+        """,
+        "used in record",
+    )
+
+    # Test promise
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          Promise<ObservableArray<boolean>> foo();
+        };
+        """,
+        "used in promise",
+    )
+
+    # Test union
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          attribute (DOMString or ObservableArray<boolean>>) foo;
+        };
+        """,
+        "used in union",
+    )
+
+    # Test dictionary member
+    harness.should_throw(
+        parser,
+        """
+        dictionary A {
+          ObservableArray<boolean> foo;
+        };
+        """,
+        "used on dictionary member type",
+    )
+
+    # Test argument
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          undefined foo(ObservableArray<boolean> foo);
+        };
+        """,
+        "used on argument",
+    )
+
+    # Test static attribute
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          static attribute ObservableArray<boolean> foo;
+        };
+        """,
+        "used on static attribute type",
+    )
+
+    # Test iterable
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          iterable<ObservableArray<boolean>>;
+        };
+        """,
+        "used in iterable",
+    )
+
+    # Test maplike
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          maplike<long, ObservableArray<boolean>>;
+        };
+        """,
+        "used in maplike",
+    )
+
+    # Test setlike
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          setlike<ObservableArray<boolean>>;
+        };
+        """,
+        "used in setlike",
+    )
+
+    # Test JS implemented interface
+    harness.should_throw(
+        parser,
+        """
+        [JSImplementation="@mozilla.org/dom/test-interface-js;1"]
+        interface A {
+          readonly attribute ObservableArray<boolean> foo;
+        };
+        """,
+        "used in JS implemented interface",
+    )
+
+    # Test namespace
+    harness.should_throw(
+        parser,
+        """
+        namespace A {
+          readonly attribute ObservableArray<boolean> foo;
+        };
+        """,
+        "used in namespaces",
+    )
+
+    # Test [Cached] extended attribute
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          [Cached, Pure]
+          readonly attribute ObservableArray<boolean> foo;
+        };
+        """,
+        "have Cached extended attribute",
+    )
+
+    # Test [StoreInSlot] extended attribute
+    harness.should_throw(
+        parser,
+        """
+        interface A {
+          [StoreInSlot, Pure]
+          readonly attribute ObservableArray<boolean> foo;
+        };
+        """,
+        "have StoreInSlot extended attribute",
+    )
+
+    # Test regular attribute
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface A {
+          readonly attribute ObservableArray<boolean> foo;
+          attribute ObservableArray<[Clamp] octet> bar;
+          attribute ObservableArray<long?> baz;
+          attribute ObservableArray<(boolean or long)> qux;
+        };
+        """
+    )
+    results = parser.finish()
+    A = results[0]
+    foo = A.members[0]
+    harness.ok(foo.readonly, "A.foo is readonly attribute")
+    harness.ok(foo.type.isObservableArray(), "A.foo is ObservableArray type")
+    harness.check(
+        foo.slotIndices[A.identifier.name], 0, "A.foo should be stored in slot"
+    )
+    bar = A.members[1]
+    harness.ok(bar.type.isObservableArray(), "A.bar is ObservableArray type")
+    harness.check(
+        bar.slotIndices[A.identifier.name], 1, "A.bar should be stored in slot"
+    )
+    harness.ok(bar.type.inner.hasClamp(), "A.bar's inner type should be clamped")
+    baz = A.members[2]
+    harness.ok(baz.type.isObservableArray(), "A.baz is ObservableArray type")
+    harness.check(
+        baz.slotIndices[A.identifier.name], 2, "A.baz should be stored in slot"
+    )
+    harness.ok(baz.type.inner.nullable(), "A.baz's inner type should be nullable")
+    qux = A.members[3]
+    harness.ok(qux.type.isObservableArray(), "A.qux is ObservableArray type")
+    harness.check(
+        qux.slotIndices[A.identifier.name], 3, "A.qux should be stored in slot"
+    )
+    harness.ok(qux.type.inner.isUnion(), "A.qux's inner type should be union")
diff --git a/dom/bindings/parser/tests/test_optional_constraints.py b/dom/bindings/parser/tests/test_optional_constraints.py
new file mode 100644
index 0000000000..34f0346762
--- /dev/null
+++ b/dom/bindings/parser/tests/test_optional_constraints.py
@@ -0,0 +1,38 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface OptionalConstraints1 {
+              undefined foo(optional byte arg1, byte arg2);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        not threw,
+        "Should not have thrown on non-optional argument following "
+        "optional argument.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface OptionalConstraints2 {
+          undefined foo(optional byte arg1 = 1, optional byte arg2 = 2,
+                        optional byte arg3, optional byte arg4 = 4,
+                        optional byte arg5, optional byte arg6 = 9);
+        };
+    """
+    )
+    results = parser.finish()
+    args = results[0].members[0].signatures()[0][1]
+    harness.check(len(args), 6, "Should have 6 arguments")
+    harness.check(args[5].defaultValue.value, 9, "Should have correct default value")
diff --git a/dom/bindings/parser/tests/test_overload.py b/dom/bindings/parser/tests/test_overload.py
new file mode 100644
index 0000000000..7816276aa6
--- /dev/null
+++ b/dom/bindings/parser/tests/test_overload.py
@@ -0,0 +1,74 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestOverloads {
+          undefined basic();
+          undefined basic(long arg1);
+          boolean abitharder(TestOverloads foo);
+          boolean abitharder(boolean foo);
+          undefined abitharder(ArrayBuffer? foo);
+          undefined withVariadics(long... numbers);
+          undefined withVariadics(TestOverloads iface);
+          undefined withVariadics(long num, TestOverloads iface);
+          undefined optionalTest();
+          undefined optionalTest(optional long num1, long num2);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(True, "TestOverloads interface parsed without error.")
+    harness.check(len(results), 1, "Should be one production.")
+    iface = results[0]
+    harness.ok(isinstance(iface, WebIDL.IDLInterface), "Should be an IDLInterface")
+    harness.check(
+        iface.identifier.QName(), "::TestOverloads", "Interface has the right QName"
+    )
+    harness.check(
+        iface.identifier.name, "TestOverloads", "Interface has the right name"
+    )
+    harness.check(len(iface.members), 4, "Expect %s members" % 4)
+
+    member = iface.members[0]
+    harness.check(
+        member.identifier.QName(),
+        "::TestOverloads::basic",
+        "Method has the right QName",
+    )
+    harness.check(member.identifier.name, "basic", "Method has the right name")
+    harness.check(member.hasOverloads(), True, "Method has overloads")
+
+    signatures = member.signatures()
+    harness.check(len(signatures), 2, "Method should have 2 signatures")
+
+    (retval, argumentSet) = signatures[0]
+
+    harness.check(str(retval), "Undefined", "Expect an undefined retval")
+    harness.check(len(argumentSet), 0, "Expect an empty argument set")
+
+    (retval, argumentSet) = signatures[1]
+    harness.check(str(retval), "Undefined", "Expect an undefined retval")
+    harness.check(len(argumentSet), 1, "Expect an argument set with one argument")
+
+    argument = argumentSet[0]
+    harness.ok(isinstance(argument, WebIDL.IDLArgument), "Should be an IDLArgument")
+    harness.check(
+        argument.identifier.QName(),
+        "::TestOverloads::basic::arg1",
+        "Argument has the right QName",
+    )
+    harness.check(argument.identifier.name, "arg1", "Argument has the right name")
+    harness.check(str(argument.type), "Long", "Argument has the right type")
+
+    member = iface.members[3]
+    harness.check(
+        len(member.overloadsForArgCount(0)), 1, "Only one overload for no args"
+    )
+    harness.check(len(member.overloadsForArgCount(1)), 0, "No overloads for one arg")
+    harness.check(
+        len(member.overloadsForArgCount(2)), 1, "Only one overload for two args"
+    )
diff --git a/dom/bindings/parser/tests/test_promise.py b/dom/bindings/parser/tests/test_promise.py
new file mode 100644
index 0000000000..1dfb6d4643
--- /dev/null
+++ b/dom/bindings/parser/tests/test_promise.py
@@ -0,0 +1,180 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              legacycaller Promise<any> foo();
+            };
+        """
+        )
+        parser.finish()
+
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow Promise return values for legacycaller.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              Promise<any> foo();
+              long foo(long arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow overloads which have both Promise and "
+        "non-Promise return types.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              long foo(long arg);
+              Promise<any> foo();
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow overloads which have both Promise and "
+        "non-Promise return types.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              Promise<any>? foo();
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow nullable Promise return values.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              undefined foo(Promise<any>? arg);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow nullable Promise arguments.")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface A {
+          Promise<any> foo();
+          Promise<any> foo(long arg);
+        };
+    """
+    )
+    parser.finish()
+
+    harness.ok(
+        True, "Should allow overloads which only have Promise and return " "types."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              attribute Promise<any> attr;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow writable Promise-typed attributes.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              [LegacyLenientSetter] readonly attribute Promise<any> attr;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should not allow [LegacyLenientSetter] Promise-typed attributes."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              [PutForwards=bar] readonly attribute Promise<any> attr;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [PutForwards] Promise-typed attributes.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              [Replaceable] readonly attribute Promise<any> attr;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [Replaceable] Promise-typed attributes.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface A {
+              [SameObject] readonly attribute Promise<any> attr;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow [SameObject] Promise-typed attributes.")
diff --git a/dom/bindings/parser/tests/test_prototype_ident.py b/dom/bindings/parser/tests/test_prototype_ident.py
new file mode 100644
index 0000000000..5e4d3a2000
--- /dev/null
+++ b/dom/bindings/parser/tests/test_prototype_ident.py
@@ -0,0 +1,110 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestIface {
+              static attribute boolean prototype;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "The identifier of a static attribute must not be 'prototype'")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestIface {
+              static boolean prototype();
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "The identifier of a static operation must not be 'prototype'")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestIface {
+              const boolean prototype = true;
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "The identifier of a constant must not be 'prototype'")
+
+    # Make sure that we can parse non-static attributes with 'prototype' as identifier.
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestIface {
+          attribute boolean prototype;
+        };
+    """
+    )
+    results = parser.finish()
+
+    testIface = results[0]
+    harness.check(
+        testIface.members[0].isStatic(), False, "Attribute should not be static"
+    )
+    harness.check(
+        testIface.members[0].identifier.name,
+        "prototype",
+        "Attribute identifier should be 'prototype'",
+    )
+
+    # Make sure that we can parse non-static operations with 'prototype' as identifier.
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestIface {
+          boolean prototype();
+        };
+    """
+    )
+    results = parser.finish()
+
+    testIface = results[0]
+    harness.check(
+        testIface.members[0].isStatic(), False, "Operation should not be static"
+    )
+    harness.check(
+        testIface.members[0].identifier.name,
+        "prototype",
+        "Operation identifier should be 'prototype'",
+    )
+
+    # Make sure that we can parse dictionary members with 'prototype' as identifier.
+    parser = parser.reset()
+    parser.parse(
+        """
+        dictionary TestDict {
+          boolean prototype;
+        };
+    """
+    )
+    results = parser.finish()
+
+    testDict = results[0]
+    harness.check(
+        testDict.members[0].identifier.name,
+        "prototype",
+        "Dictionary member should be 'prototype'",
+    )
diff --git a/dom/bindings/parser/tests/test_putForwards.py b/dom/bindings/parser/tests/test_putForwards.py
new file mode 100644
index 0000000000..e32e6c14f7
--- /dev/null
+++ b/dom/bindings/parser/tests/test_putForwards.py
@@ -0,0 +1,122 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface I {
+              [PutForwards=B] readonly attribute long A;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface I {
+              [PutForwards=B] readonly attribute J A;
+            };
+            interface J {
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface I {
+              [PutForwards=B] attribute J A;
+            };
+            interface J {
+              attribute long B;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface I {
+              [PutForwards=B] static readonly attribute J A;
+            };
+            interface J {
+              attribute long B;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            callback interface I {
+              [PutForwards=B] readonly attribute J A;
+            };
+            interface J {
+              attribute long B;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface I {
+              [PutForwards=C] readonly attribute J A;
+              [PutForwards=C] readonly attribute J B;
+            };
+            interface J {
+              [PutForwards=D] readonly attribute K C;
+            };
+            interface K {
+              [PutForwards=A] readonly attribute I D;
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_record.py b/dom/bindings/parser/tests/test_record.py
new file mode 100644
index 0000000000..bee5c83953
--- /dev/null
+++ b/dom/bindings/parser/tests/test_record.py
@@ -0,0 +1,61 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        dictionary Dict {};
+        interface RecordArg {
+          undefined foo(record<DOMString, Dict> arg);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 2, "Should know about two things")
+    harness.ok(
+        isinstance(results[1], WebIDL.IDLInterface), "Should have an interface here"
+    )
+    members = results[1].members
+    harness.check(len(members), 1, "Should have one member")
+    harness.ok(members[0].isMethod(), "Should have method")
+    signature = members[0].signatures()[0]
+    args = signature[1]
+    harness.check(len(args), 1, "Should have one arg")
+    harness.ok(args[0].type.isRecord(), "Should have a record type here")
+    harness.ok(args[0].type.inner.isDictionary(), "Should have a dictionary inner type")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface RecordUndefinedArg {
+              undefined foo(record<DOMString, undefined> arg);
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "Should have thrown because record can't have undefined as value type."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            dictionary Dict {
+              record<DOMString, Dict> val;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown on dictionary containing itself via record.")
diff --git a/dom/bindings/parser/tests/test_replaceable.py b/dom/bindings/parser/tests/test_replaceable.py
new file mode 100644
index 0000000000..3b0a6fea36
--- /dev/null
+++ b/dom/bindings/parser/tests/test_replaceable.py
@@ -0,0 +1,86 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import WebIDL
+
+
+def should_throw(parser, harness, message, code):
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(code)
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown: %s" % message)
+
+
+def WebIDLTest(parser, harness):
+    # The [Replaceable] extended attribute MUST take no arguments.
+    should_throw(
+        parser,
+        harness,
+        "no arguments",
+        """
+        interface I {
+          [Replaceable=X] readonly attribute long A;
+        };
+    """,
+    )
+
+    # An attribute with the [Replaceable] extended attribute MUST NOT also be
+    # declared with the [PutForwards] extended attribute.
+    should_throw(
+        parser,
+        harness,
+        "PutForwards",
+        """
+        interface I {
+          [PutForwards=B, Replaceable] readonly attribute J A;
+        };
+        interface J {
+          attribute long B;
+        };
+    """,
+    )
+
+    # The [Replaceable] extended attribute MUST NOT be used on an attribute
+    # that is not read only.
+    should_throw(
+        parser,
+        harness,
+        "writable attribute",
+        """
+        interface I {
+          [Replaceable] attribute long A;
+        };
+    """,
+    )
+
+    # The [Replaceable] extended attribute MUST NOT be used on a static
+    # attribute.
+    should_throw(
+        parser,
+        harness,
+        "static attribute",
+        """
+        interface I {
+          [Replaceable] static readonly attribute long A;
+        };
+    """,
+    )
+
+    # The [Replaceable] extended attribute MUST NOT be used on an attribute
+    # declared on a callback interface.
+    should_throw(
+        parser,
+        harness,
+        "callback interface",
+        """
+        callback interface I {
+          [Replaceable] readonly attribute long A;
+        };
+    """,
+    )
diff --git a/dom/bindings/parser/tests/test_sanity.py b/dom/bindings/parser/tests/test_sanity.py
new file mode 100644
index 0000000000..d3184c0073
--- /dev/null
+++ b/dom/bindings/parser/tests/test_sanity.py
@@ -0,0 +1,7 @@
+def WebIDLTest(parser, harness):
+    parser.parse("")
+    parser.finish()
+    harness.ok(True, "Parsing nothing doesn't throw.")
+    parser.parse("interface Foo {};")
+    parser.finish()
+    harness.ok(True, "Parsing a silly interface doesn't throw.")
diff --git a/dom/bindings/parser/tests/test_securecontext_extended_attribute.py b/dom/bindings/parser/tests/test_securecontext_extended_attribute.py
new file mode 100644
index 0000000000..4dd0811ed7
--- /dev/null
+++ b/dom/bindings/parser/tests/test_securecontext_extended_attribute.py
@@ -0,0 +1,541 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        [SecureContext]
+        interface TestSecureContextOnInterface {
+          const octet TEST_CONSTANT = 0;
+          readonly attribute byte testAttribute;
+          undefined testMethod(byte foo);
+        };
+        partial interface TestSecureContextOnInterface {
+          const octet TEST_CONSTANT_2 = 0;
+          readonly attribute byte testAttribute2;
+          undefined testMethod2(byte foo);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        6,
+        "TestSecureContextOnInterface should have six members",
+    )
+    harness.ok(
+        results[0].getExtendedAttribute("SecureContext"),
+        "Interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to constant members",
+    )
+    harness.ok(
+        results[0].members[1].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to attribute members",
+    )
+    harness.ok(
+        results[0].members[2].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to method members",
+    )
+    harness.ok(
+        results[0].members[3].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to "
+            "constant members from partial interface"
+        ),
+    )
+    harness.ok(
+        results[0].members[4].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to "
+            "attribute members from partial interface"
+        ),
+    )
+    harness.ok(
+        results[0].members[5].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to method members from partial interface",
+    )
+
+    # Same thing, but with the partial interface specified first:
+    parser = parser.reset()
+    parser.parse(
+        """
+        partial interface TestSecureContextOnInterfaceAfterPartialInterface {
+          const octet TEST_CONSTANT_2 = 0;
+          readonly attribute byte testAttribute2;
+          undefined testMethod2(byte foo);
+        };
+        [SecureContext]
+        interface TestSecureContextOnInterfaceAfterPartialInterface {
+          const octet TEST_CONSTANT = 0;
+          readonly attribute byte testAttribute;
+          undefined testMethod(byte foo);
+        };
+     """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[1].members),
+        6,
+        "TestSecureContextOnInterfaceAfterPartialInterface should have six members",
+    )
+    harness.ok(
+        results[1].getExtendedAttribute("SecureContext"),
+        "Interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[1].members[0].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to constant members",
+    )
+    harness.ok(
+        results[1].members[1].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to attribute members",
+    )
+    harness.ok(
+        results[1].members[2].getExtendedAttribute("SecureContext"),
+        "[SecureContext] should propagate from interface to method members",
+    )
+    harness.ok(
+        results[1].members[3].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to constant members from "
+            "partial interface"
+        ),
+    )
+    harness.ok(
+        results[1].members[4].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to attribute members from "
+            "partial interface"
+        ),
+    )
+    harness.ok(
+        results[1].members[5].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to method members from partial "
+            "interface"
+        ),
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestSecureContextOnPartialInterface {
+          const octet TEST_CONSTANT = 0;
+          readonly attribute byte testAttribute;
+          undefined testMethod(byte foo);
+        };
+        [SecureContext]
+        partial interface TestSecureContextOnPartialInterface {
+          const octet TEST_CONSTANT_2 = 0;
+          readonly attribute byte testAttribute2;
+          undefined testMethod2(byte foo);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        6,
+        "TestSecureContextOnPartialInterface should have six members",
+    )
+    harness.ok(
+        results[0].getExtendedAttribute("SecureContext") is None,
+        "[SecureContext] should not propagate from a partial interface to the interface",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext") is None,
+        (
+            "[SecureContext] should not propagate from a partial interface to the interface's "
+            "constant members"
+        ),
+    )
+    harness.ok(
+        results[0].members[1].getExtendedAttribute("SecureContext") is None,
+        (
+            "[SecureContext] should not propagate from a partial interface to the interface's "
+            "attribute members"
+        ),
+    )
+    harness.ok(
+        results[0].members[2].getExtendedAttribute("SecureContext") is None,
+        (
+            "[SecureContext] should not propagate from a partial interface to the interface's "
+            "method members"
+        ),
+    )
+    harness.ok(
+        results[0].members[3].getExtendedAttribute("SecureContext"),
+        "Constant members from [SecureContext] partial interface should be [SecureContext]",
+    )
+    harness.ok(
+        results[0].members[4].getExtendedAttribute("SecureContext"),
+        "Attribute members from [SecureContext] partial interface should be [SecureContext]",
+    )
+    harness.ok(
+        results[0].members[5].getExtendedAttribute("SecureContext"),
+        "Method members from [SecureContext] partial interface should be [SecureContext]",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestSecureContextOnInterfaceMembers {
+          const octet TEST_NON_SECURE_CONSTANT_1 = 0;
+          [SecureContext]
+          const octet TEST_SECURE_CONSTANT       = 1;
+          const octet TEST_NON_SECURE_CONSTANT_2 = 2;
+          readonly attribute byte testNonSecureAttribute1;
+          [SecureContext]
+          readonly attribute byte testSecureAttribute;
+          readonly attribute byte testNonSecureAttribute2;
+          undefined testNonSecureMethod1(byte foo);
+          [SecureContext]
+          undefined testSecureMethod(byte foo);
+          undefined testNonSecureMethod2(byte foo);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        9,
+        "TestSecureContextOnInterfaceMembers should have nine members",
+    )
+    harness.ok(
+        results[0].getExtendedAttribute("SecureContext") is None,
+        "[SecureContext] on members should not propagate up to the interface",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext") is None,
+        "Constant should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[1].getExtendedAttribute("SecureContext"),
+        "Constant should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[2].getExtendedAttribute("SecureContext") is None,
+        "Constant should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[3].getExtendedAttribute("SecureContext") is None,
+        "Attribute should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[4].getExtendedAttribute("SecureContext"),
+        "Attribute should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[5].getExtendedAttribute("SecureContext") is None,
+        "Attribute should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[6].getExtendedAttribute("SecureContext") is None,
+        "Method should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[7].getExtendedAttribute("SecureContext"),
+        "Method should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[8].getExtendedAttribute("SecureContext") is None,
+        "Method should not have [SecureContext] extended attribute",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestSecureContextOnPartialInterfaceMembers {
+        };
+        partial interface TestSecureContextOnPartialInterfaceMembers {
+          const octet TEST_NON_SECURE_CONSTANT_1 = 0;
+          [SecureContext]
+          const octet TEST_SECURE_CONSTANT       = 1;
+          const octet TEST_NON_SECURE_CONSTANT_2 = 2;
+          readonly attribute byte testNonSecureAttribute1;
+          [SecureContext]
+          readonly attribute byte testSecureAttribute;
+          readonly attribute byte testNonSecureAttribute2;
+          undefined testNonSecureMethod1(byte foo);
+          [SecureContext]
+          undefined testSecureMethod(byte foo);
+          undefined testNonSecureMethod2(byte foo);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        9,
+        "TestSecureContextOnPartialInterfaceMembers should have nine members",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext") is None,
+        "Constant from partial interface should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[1].getExtendedAttribute("SecureContext"),
+        "Constant from partial interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[2].getExtendedAttribute("SecureContext") is None,
+        "Constant from partial interface should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[3].getExtendedAttribute("SecureContext") is None,
+        "Attribute from partial interface should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[4].getExtendedAttribute("SecureContext"),
+        "Attribute from partial interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[5].getExtendedAttribute("SecureContext") is None,
+        "Attribute from partial interface should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[6].getExtendedAttribute("SecureContext") is None,
+        "Method from partial interface should not have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[7].getExtendedAttribute("SecureContext"),
+        "Method from partial interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[8].getExtendedAttribute("SecureContext") is None,
+        "Method from partial interface should not have [SecureContext] extended attribute",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SecureContext=something]
+            interface TestSecureContextTakesNoValue1 {
+              const octet TEST_SECURE_CONSTANT = 0;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "[SecureContext] must take no arguments (testing on interface)")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestSecureContextForOverloads1 {
+              [SecureContext]
+              undefined testSecureMethod(byte foo);
+            };
+            partial interface TestSecureContextForOverloads1 {
+              undefined testSecureMethod(byte foo, byte bar);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        (
+            "If [SecureContext] appears on an overloaded operation, then it MUST appear on all "
+            "overloads"
+        ),
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestSecureContextForOverloads2 {
+              [SecureContext]
+              undefined testSecureMethod(byte foo);
+            };
+            partial interface TestSecureContextForOverloads2 {
+              [SecureContext]
+              undefined testSecureMethod(byte foo, byte bar);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        not threw,
+        "[SecureContext] can appear on an overloaded operation if it appears on all overloads",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SecureContext]
+            interface TestSecureContextOnInterfaceAndMember {
+              [SecureContext]
+              undefined testSecureMethod(byte foo);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw, "[SecureContext] must not appear on an interface and interface member"
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestSecureContextOnPartialInterfaceAndMember {
+            };
+            [SecureContext]
+            partial interface TestSecureContextOnPartialInterfaceAndMember {
+              [SecureContext]
+              undefined testSecureMethod(byte foo);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        (
+            "[SecureContext] must not appear on a partial interface and one of the partial "
+            "interface's member's"
+        ),
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SecureContext]
+            interface TestSecureContextOnInterfaceAndPartialInterfaceMember {
+            };
+            partial interface TestSecureContextOnInterfaceAndPartialInterfaceMember {
+              [SecureContext]
+              undefined testSecureMethod(byte foo);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        (
+            "[SecureContext] must not appear on an interface and one of its partial interface's "
+            "member's"
+        ),
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [SecureContext]
+            interface TestSecureContextOnInheritedInterface {
+            };
+            interface TestSecureContextNotOnInheritingInterface : TestSecureContextOnInheritedInterface {
+              undefined testSecureMethod(byte foo);
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        (
+            "[SecureContext] must appear on interfaces that inherit from another [SecureContext] "
+            "interface"
+        ),
+    )
+
+    # Test 'includes'.
+    parser = parser.reset()
+    parser.parse(
+        """
+        [SecureContext]
+        interface TestSecureContextInterfaceThatIncludesNonSecureContextMixin {
+          const octet TEST_CONSTANT = 0;
+        };
+        interface mixin TestNonSecureContextMixin {
+          const octet TEST_CONSTANT_2 = 0;
+          readonly attribute byte testAttribute2;
+          undefined testMethod2(byte foo);
+        };
+        TestSecureContextInterfaceThatIncludesNonSecureContextMixin includes TestNonSecureContextMixin;
+     """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        4,
+        (
+            "TestSecureContextInterfaceThatImplementsNonSecureContextInterface should have four "
+            "members"
+        ),
+    )
+    harness.ok(
+        results[0].getExtendedAttribute("SecureContext"),
+        "Interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext"),
+        (
+            "[SecureContext] should propagate from interface to constant members even when other "
+            "members are copied from a non-[SecureContext] interface"
+        ),
+    )
+    harness.ok(
+        results[0].members[1].getExtendedAttribute("SecureContext") is None,
+        "Constants copied from non-[SecureContext] mixin should not be [SecureContext]",
+    )
+    harness.ok(
+        results[0].members[2].getExtendedAttribute("SecureContext") is None,
+        "Attributes copied from non-[SecureContext] mixin should not be [SecureContext]",
+    )
+    harness.ok(
+        results[0].members[3].getExtendedAttribute("SecureContext") is None,
+        "Methods copied from non-[SecureContext] mixin should not be [SecureContext]",
+    )
+
+    # Test SecureContext and LegacyNoInterfaceObject
+    parser = parser.reset()
+    parser.parse(
+        """
+        [LegacyNoInterfaceObject, SecureContext]
+        interface TestSecureContextLegacyNoInterfaceObject {
+          undefined testSecureMethod(byte foo);
+        };
+    """
+    )
+    results = parser.finish()
+    harness.check(
+        len(results[0].members),
+        1,
+        "TestSecureContextLegacyNoInterfaceObject should have only one member",
+    )
+    harness.ok(
+        results[0].getExtendedAttribute("SecureContext"),
+        "Interface should have [SecureContext] extended attribute",
+    )
+    harness.ok(
+        results[0].members[0].getExtendedAttribute("SecureContext"),
+        "Interface member should have [SecureContext] extended attribute",
+    )
diff --git a/dom/bindings/parser/tests/test_special_method_signature_mismatch.py b/dom/bindings/parser/tests/test_special_method_signature_mismatch.py
new file mode 100644
index 0000000000..5dd581985b
--- /dev/null
+++ b/dom/bindings/parser/tests/test_special_method_signature_mismatch.py
@@ -0,0 +1,259 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch1 {
+              getter long long foo(long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch2 {
+              getter undefined foo(unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch3 {
+              getter boolean foo(unsigned long index, boolean extraArg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch4 {
+              getter boolean foo(unsigned long... index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch5 {
+              getter boolean foo(optional unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch6 {
+              getter boolean foo();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch7 {
+              deleter long long foo(long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch9 {
+              deleter boolean foo(unsigned long index, boolean extraArg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch10 {
+              deleter boolean foo(unsigned long... index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch11 {
+              deleter boolean foo(optional unsigned long index);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch12 {
+              deleter boolean foo();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch13 {
+              setter long long foo(long index, long long value);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch15 {
+              setter boolean foo(unsigned long index, boolean value, long long extraArg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch16 {
+              setter boolean foo(unsigned long index, boolean... value);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch17 {
+              setter boolean foo(unsigned long index, optional boolean value);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodSignatureMismatch18 {
+              setter boolean foo();
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_special_methods.py b/dom/bindings/parser/tests/test_special_methods.py
new file mode 100644
index 0000000000..911bb8ec0d
--- /dev/null
+++ b/dom/bindings/parser/tests/test_special_methods.py
@@ -0,0 +1,117 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface SpecialMethods {
+          getter long long (unsigned long index);
+          setter long long (unsigned long index, long long value);
+          getter boolean (DOMString name);
+          setter boolean (DOMString name, boolean value);
+          deleter boolean (DOMString name);
+          readonly attribute unsigned long length;
+        };
+
+        interface SpecialMethodsCombination {
+          getter deleter boolean (DOMString name);
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    def checkMethod(
+        method,
+        QName,
+        name,
+        static=False,
+        getter=False,
+        setter=False,
+        deleter=False,
+        legacycaller=False,
+        stringifier=False,
+    ):
+        harness.ok(isinstance(method, WebIDL.IDLMethod), "Should be an IDLMethod")
+        harness.check(method.identifier.QName(), QName, "Method has the right QName")
+        harness.check(method.identifier.name, name, "Method has the right name")
+        harness.check(method.isStatic(), static, "Method has the correct static value")
+        harness.check(method.isGetter(), getter, "Method has the correct getter value")
+        harness.check(method.isSetter(), setter, "Method has the correct setter value")
+        harness.check(
+            method.isDeleter(), deleter, "Method has the correct deleter value"
+        )
+        harness.check(
+            method.isLegacycaller(),
+            legacycaller,
+            "Method has the correct legacycaller value",
+        )
+        harness.check(
+            method.isStringifier(),
+            stringifier,
+            "Method has the correct stringifier value",
+        )
+
+    harness.check(len(results), 2, "Expect 2 interfaces")
+
+    iface = results[0]
+    harness.check(len(iface.members), 6, "Expect 6 members")
+
+    checkMethod(
+        iface.members[0],
+        "::SpecialMethods::__indexedgetter",
+        "__indexedgetter",
+        getter=True,
+    )
+    checkMethod(
+        iface.members[1],
+        "::SpecialMethods::__indexedsetter",
+        "__indexedsetter",
+        setter=True,
+    )
+    checkMethod(
+        iface.members[2],
+        "::SpecialMethods::__namedgetter",
+        "__namedgetter",
+        getter=True,
+    )
+    checkMethod(
+        iface.members[3],
+        "::SpecialMethods::__namedsetter",
+        "__namedsetter",
+        setter=True,
+    )
+    checkMethod(
+        iface.members[4],
+        "::SpecialMethods::__nameddeleter",
+        "__nameddeleter",
+        deleter=True,
+    )
+
+    iface = results[1]
+    harness.check(len(iface.members), 1, "Expect 1 member")
+
+    checkMethod(
+        iface.members[0],
+        "::SpecialMethodsCombination::__namedgetterdeleter",
+        "__namedgetterdeleter",
+        getter=True,
+        deleter=True,
+    )
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface IndexedDeleter {
+              deleter undefined(unsigned long index);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "There are no indexed deleters")
diff --git a/dom/bindings/parser/tests/test_special_methods_uniqueness.py b/dom/bindings/parser/tests/test_special_methods_uniqueness.py
new file mode 100644
index 0000000000..948c639204
--- /dev/null
+++ b/dom/bindings/parser/tests/test_special_methods_uniqueness.py
@@ -0,0 +1,54 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodUniqueness1 {
+              getter deleter boolean (DOMString name);
+              getter boolean (DOMString name);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodUniqueness1 {
+              deleter boolean (DOMString name);
+              getter deleter boolean (DOMString name);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface SpecialMethodUniqueness1 {
+              setter boolean (DOMString name);
+              setter boolean (DOMString name);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_stringifier.py b/dom/bindings/parser/tests/test_stringifier.py
new file mode 100644
index 0000000000..c2052c44e5
--- /dev/null
+++ b/dom/bindings/parser/tests/test_stringifier.py
@@ -0,0 +1,196 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestStringifier {
+          stringifier;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.ok(
+        isinstance(results[0].members[0], WebIDL.IDLMethod),
+        "Stringifer should be method",
+    )
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestStringifier {
+              stringifier;
+              stringifier;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow two 'stringifier;'")
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestStringifier {
+              stringifier;
+              stringifier DOMString foo();
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow a 'stringifier;' and a 'stringifier()'")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestStringifier {
+            stringifier attribute DOMString foo;
+        };
+    """
+    )
+    results = parser.finish()
+    harness.ok(
+        isinstance(results[0].members[0], WebIDL.IDLAttribute),
+        "Stringifier attribute should be an attribute",
+    )
+    stringifier = results[0].members[1]
+    harness.ok(
+        isinstance(stringifier, WebIDL.IDLMethod),
+        "Stringifier attribute should insert a method",
+    )
+    harness.ok(stringifier.isStringifier(), "Inserted method should be a stringifier")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestStringifier {};
+        interface mixin TestStringifierMixin {
+            stringifier attribute DOMString foo;
+        };
+        TestStringifier includes TestStringifierMixin;
+    """
+    )
+    results = parser.finish()
+    harness.ok(
+        isinstance(results[0].members[0], WebIDL.IDLAttribute),
+        "Stringifier attribute should be an attribute",
+    )
+    stringifier = results[0].members[1]
+    harness.ok(
+        isinstance(stringifier, WebIDL.IDLMethod),
+        "Stringifier attribute should insert a method",
+    )
+    harness.ok(stringifier.isStringifier(), "Inserted method should be a stringifier")
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestStringifier {
+            stringifier attribute USVString foo;
+        };
+    """
+    )
+    results = parser.finish()
+    stringifier = results[0].members[1]
+    harness.ok(
+        stringifier.signatures()[0][0].isUSVString(),
+        "Stringifier attributes should allow USVString",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestStringifier {
+            [Throws, NeedsSubjectPrincipal]
+            stringifier attribute USVString foo;
+        };
+    """
+    )
+    results = parser.finish()
+    stringifier = results[0].members[1]
+    harness.ok(
+        stringifier.getExtendedAttribute("Throws"),
+        "Stringifier attributes should support [Throws]",
+    )
+    harness.ok(
+        stringifier.getExtendedAttribute("NeedsSubjectPrincipal"),
+        "Stringifier attributes should support [NeedsSubjectPrincipal]",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface TestStringifier {
+            stringifier attribute UTF8String foo;
+        };
+    """
+    )
+    results = parser.finish()
+    stringifier = results[0].members[1]
+    harness.ok(
+        stringifier.signatures()[0][0].isUTF8String(),
+        "Stringifier attributes should allow UTF8String",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestStringifier {
+              stringifier attribute ByteString foo;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow ByteString")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestStringifier {
+              stringifier;
+              stringifier attribute DOMString foo;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow a 'stringifier;' and a stringifier attribute")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface TestStringifier {
+              stringifier attribute DOMString foo;
+              stringifier attribute DOMString bar;
+            };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should not allow multiple stringifier attributes")
diff --git a/dom/bindings/parser/tests/test_toJSON.py b/dom/bindings/parser/tests/test_toJSON.py
new file mode 100644
index 0000000000..ec81080bec
--- /dev/null
+++ b/dom/bindings/parser/tests/test_toJSON.py
@@ -0,0 +1,312 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              object toJSON();
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow a toJSON method.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              object toJSON(object arg);
+              object toJSON(long arg);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow overloads of a toJSON method.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              object toJSON(object arg);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should not allow a toJSON method with arguments.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              long toJSON();
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(not threw, "Should allow a toJSON method with 'long' as return type.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              [Default] object toJSON();
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        not threw, "Should allow a default toJSON method with 'object' as return type."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Test {
+              [Default] long toJSON();
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should not allow a default toJSON method with non-'object' as return type.",
+    )
+
+    JsonTypes = [
+        "byte",
+        "octet",
+        "short",
+        "unsigned short",
+        "long",
+        "unsigned long",
+        "long long",
+        "unsigned long long",
+        "float",
+        "unrestricted float",
+        "double",
+        "unrestricted double",
+        "boolean",
+        "DOMString",
+        "ByteString",
+        "UTF8String",
+        "USVString",
+        "Enum",
+        "InterfaceWithToJSON",
+        "object",
+    ]
+
+    nonJsonTypes = [
+        "InterfaceWithoutToJSON",
+        "any",
+        "Int8Array",
+        "Int16Array",
+        "Int32Array",
+        "Uint8Array",
+        "Uint16Array",
+        "Uint32Array",
+        "Uint8ClampedArray",
+        "Float32Array",
+        "Float64Array",
+        "ArrayBuffer",
+    ]
+
+    def doTest(testIDL, shouldThrow, description):
+        p = parser.reset()
+        threw = False
+        try:
+            p.parse(
+                testIDL
+                + """
+                enum Enum { "a", "b", "c" };
+                interface InterfaceWithToJSON { long toJSON(); };
+                interface InterfaceWithoutToJSON {};
+                """
+            )
+            p.finish()
+        except Exception as x:
+            threw = True
+            harness.ok(x.message == "toJSON method has non-JSON return type", x)
+        harness.check(threw, shouldThrow, description)
+
+    for type in JsonTypes:
+        doTest(
+            "interface Test { %s toJSON(); };" % type,
+            False,
+            "%s should be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { sequence<%s> toJSON(); };" % type,
+            False,
+            "sequence<%s> should be a JSON type" % type,
+        )
+
+        doTest(
+            "dictionary Foo { %s foo; }; " "interface Test { Foo toJSON(); }; " % type,
+            False,
+            "dictionary containing only JSON type (%s) should be a JSON type" % type,
+        )
+
+        doTest(
+            "dictionary Foo { %s foo; }; dictionary Bar : Foo { }; "
+            "interface Test { Bar toJSON(); }; " % type,
+            False,
+            "dictionary whose ancestors only contain JSON types should be a JSON type",
+        )
+
+        doTest(
+            "dictionary Foo { any foo; }; dictionary Bar : Foo { %s bar; };"
+            "interface Test { Bar toJSON(); };" % type,
+            True,
+            "dictionary whose ancestors contain non-JSON types should not be a JSON type",
+        )
+
+        doTest(
+            "interface Test { record<DOMString, %s> toJSON(); };" % type,
+            False,
+            "record<DOMString, %s> should be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { record<ByteString, %s> toJSON(); };" % type,
+            False,
+            "record<ByteString, %s> should be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { record<UTF8String, %s> toJSON(); };" % type,
+            False,
+            "record<UTF8String, %s> should be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { record<USVString, %s> toJSON(); };" % type,
+            False,
+            "record<USVString, %s> should be a JSON type" % type,
+        )
+
+        otherUnionType = "Foo" if type != "object" else "long"
+        doTest(
+            "interface Foo { object toJSON(); };"
+            "interface Test { (%s or %s) toJSON(); };" % (otherUnionType, type),
+            False,
+            "union containing only JSON types (%s or %s) should be a JSON type"
+            % (otherUnionType, type),
+        )
+
+        doTest(
+            "interface test { %s? toJSON(); };" % type,
+            False,
+            "Nullable type (%s) should be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Foo : InterfaceWithoutToJSON { %s toJSON(); };"
+            "interface Test { Foo toJSON(); };" % type,
+            False,
+            "interface with toJSON should be a JSON type",
+        )
+
+    doTest(
+        "interface Foo : InterfaceWithToJSON { };" "interface Test { Foo toJSON(); };",
+        False,
+        "inherited interface with toJSON should be a JSON type",
+    )
+
+    for type in nonJsonTypes:
+        doTest(
+            "interface Test { %s toJSON(); };" % type,
+            True,
+            "%s should not be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { sequence<%s> toJSON(); };" % type,
+            True,
+            "sequence<%s> should not be a JSON type" % type,
+        )
+
+        doTest(
+            "dictionary Foo { %s foo; }; " "interface Test { Foo toJSON(); }; " % type,
+            True,
+            "Dictionary containing a non-JSON type (%s) should not be a JSON type"
+            % type,
+        )
+
+        doTest(
+            "dictionary Foo { %s foo; }; dictionary Bar : Foo { }; "
+            "interface Test { Bar toJSON(); }; " % type,
+            True,
+            "dictionary whose ancestors only contain non-JSON types should not be a JSON type",
+        )
+
+        doTest(
+            "interface Test { record<DOMString, %s> toJSON(); };" % type,
+            True,
+            "record<DOMString, %s> should not be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { record<ByteString, %s> toJSON(); };" % type,
+            True,
+            "record<ByteString, %s> should not be a JSON type" % type,
+        )
+
+        doTest(
+            "interface Test { record<USVString, %s> toJSON(); };" % type,
+            True,
+            "record<USVString, %s> should not be a JSON type" % type,
+        )
+
+        if type != "any":
+            doTest(
+                "interface Foo { object toJSON(); }; "
+                "interface Test { (Foo or %s) toJSON(); };" % type,
+                True,
+                "union containing a non-JSON type (%s) should not be a JSON type"
+                % type,
+            )
+
+            doTest(
+                "interface test { %s? toJSON(); };" % type,
+                True,
+                "Nullable type (%s) should not be a JSON type" % type,
+            )
+
+    doTest(
+        "dictionary Foo { long foo; any bar; };" "interface Test { Foo toJSON(); };",
+        True,
+        "dictionary containing a non-JSON type should not be a JSON type",
+    )
+
+    doTest(
+        "interface Foo : InterfaceWithoutToJSON { }; "
+        "interface Test { Foo toJSON(); };",
+        True,
+        "interface without toJSON should not be a JSON type",
+    )
diff --git a/dom/bindings/parser/tests/test_treatNonCallableAsNull.py b/dom/bindings/parser/tests/test_treatNonCallableAsNull.py
new file mode 100644
index 0000000000..8ad7f942b1
--- /dev/null
+++ b/dom/bindings/parser/tests/test_treatNonCallableAsNull.py
@@ -0,0 +1,80 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        [TreatNonCallableAsNull] callback Function = any(any... arguments);
+
+        interface TestTreatNonCallableAsNull1 {
+          attribute Function? onfoo;
+          attribute Function onbar;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    iface = results[1]
+    attr = iface.members[0]
+    harness.check(attr.type.treatNonCallableAsNull(), True, "Got the expected value")
+    attr = iface.members[1]
+    harness.check(attr.type.treatNonCallableAsNull(), False, "Got the expected value")
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            callback Function = any(any... arguments);
+
+            interface TestTreatNonCallableAsNull2 {
+              [TreatNonCallableAsNull] attribute Function onfoo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            callback Function = any(any... arguments);
+
+            [TreatNonCallableAsNull]
+            interface TestTreatNonCallableAsNull3 {
+               attribute Function onfoo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+
+    threw = False
+    try:
+        parser.parse(
+            """
+            [TreatNonCallableAsNull, LegacyTreatNonObjectAsNull]
+            callback Function = any(any... arguments);
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_typedef.py b/dom/bindings/parser/tests/test_typedef.py
new file mode 100644
index 0000000000..58c17135de
--- /dev/null
+++ b/dom/bindings/parser/tests/test_typedef.py
@@ -0,0 +1,97 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+      typedef long mylong;
+      typedef long? mynullablelong;
+      interface Foo {
+        const mylong X = 5;
+        undefined foo(optional mynullablelong arg = 7);
+        undefined bar(optional mynullablelong arg = null);
+        undefined baz(mylong arg);
+      };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(
+        results[2].members[1].signatures()[0][1][0].type.name,
+        "LongOrNull",
+        "Should expand typedefs",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          typedef long? mynullablelong;
+          interface Foo {
+            undefined foo(mynullablelong? Y);
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on nullable inside nullable arg.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          typedef long? mynullablelong;
+          interface Foo {
+            const mynullablelong? X = 5;
+          };
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on nullable inside nullable const.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+          interface Foo {
+            const mynullablelong? X = 5;
+          };
+          typedef long? mynullablelong;
+        """
+        )
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown on nullable inside nullable const typedef "
+        "after interface.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+      interface Foo {
+        const mylong X = 5;
+      };
+      typedef long mylong;
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(
+        results[0].members[0].type.name,
+        "Long",
+        "Should expand typedefs that come before interface",
+    )
diff --git a/dom/bindings/parser/tests/test_typedef_identifier_conflict.py b/dom/bindings/parser/tests/test_typedef_identifier_conflict.py
new file mode 100644
index 0000000000..90e45ddb7d
--- /dev/null
+++ b/dom/bindings/parser/tests/test_typedef_identifier_conflict.py
@@ -0,0 +1,19 @@
+def WebIDLTest(parser, harness):
+    exception = None
+    try:
+        parser.parse(
+            """
+            typedef long foo;
+            typedef long foo;
+            """
+        )
+
+        parser.finish()
+    except Exception as e:
+        exception = e
+
+    harness.ok(exception, "Should have thrown.")
+    harness.ok(
+        "Multiple unresolvable definitions of identifier 'foo'" in str(exception),
+        "Should have a sane exception message",
+    )
diff --git a/dom/bindings/parser/tests/test_undefined.py b/dom/bindings/parser/tests/test_undefined.py
new file mode 100644
index 0000000000..34d1ac824e
--- /dev/null
+++ b/dom/bindings/parser/tests/test_undefined.py
@@ -0,0 +1,246 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    try:
+        parser.parse(
+            """
+            dictionary Dict {
+              undefined undefinedMember;
+              double bar;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "undefined must not be used as the type of a dictionary member")
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            dictionary Dict {
+              (undefined or double) undefinedMemberOfUnionInDict;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of a dictionary member, "
+        "whether directly or in a union",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              double bar(undefined foo);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a regular operation)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              getter double(undefined name);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a getter)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              setter undefined(DOMString name, undefined value);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a setter)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              deleter undefined (undefined name);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a deleter)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              constructor (undefined foo);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a constructor)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            callback Callback = undefined (undefined foo);
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a callback)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              async iterable(undefined name);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of an async iterable "
+        "iterator)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              static double bar(undefined foo);
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined must not be used as the type of an argument in any "
+        "circumstance (so not as the argument of a static operation)",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              const undefined FOO = undefined;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined is not a valid type for a constant",
+    )
+
+    parser = parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface Foo {
+              const any FOO = undefined;
+            };
+            """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "undefined is not a valid value for a constant",
+    )
diff --git a/dom/bindings/parser/tests/test_unenumerable_own_properties.py b/dom/bindings/parser/tests/test_unenumerable_own_properties.py
new file mode 100644
index 0000000000..f465598efd
--- /dev/null
+++ b/dom/bindings/parser/tests/test_unenumerable_own_properties.py
@@ -0,0 +1,73 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface Foo {};
+        [LegacyUnenumerableNamedProperties]
+        interface Bar : Foo {
+          getter long(DOMString name);
+        };
+        interface Baz : Bar {
+          getter long(DOMString name);
+        };
+        """
+    )
+    results = parser.finish()
+    harness.check(len(results), 3, "Should have three interfaces")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyUnenumerableNamedProperties]
+            interface NoNamedGetter {
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyUnenumerableNamedProperties=Foo]
+            interface ShouldNotHaveArg {
+              getter long(DOMString name);
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            [LegacyUnenumerableNamedProperties]
+            interface Foo {
+              getter long(DOMString name);
+            };
+            interface Bar : Foo {};
+            [LegacyUnenumerableNamedProperties]
+            interface Baz : Bar {
+              getter long(DOMString name);
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_unforgeable.py b/dom/bindings/parser/tests/test_unforgeable.py
new file mode 100644
index 0000000000..0f7d52349a
--- /dev/null
+++ b/dom/bindings/parser/tests/test_unforgeable.py
@@ -0,0 +1,314 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+            interface Child : Parent {
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results),
+        2,
+        "Should be able to inherit from an interface with "
+        "[LegacyUnforgeable] properties.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+            interface Child : Parent {
+              const short foo = 10;
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results),
+        2,
+        "Should be able to inherit from an interface with "
+        "[LegacyUnforgeable] properties even if we have a constant with "
+        "the same name.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+            interface Child : Parent {
+              static attribute short foo;
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results),
+        2,
+        "Should be able to inherit from an interface with "
+        "[LegacyUnforgeable] properties even if we have a static attribute "
+        "with the same name.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+            interface Child : Parent {
+              static undefined foo();
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results),
+        2,
+        "Should be able to inherit from an interface with "
+        "[LegacyUnforgeable] properties even if we have a static operation "
+        "with the same name.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+              undefined foo();
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should have thrown when shadowing unforgeable attribute on "
+        "parent with operation.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+              undefined foo();
+            };
+            interface Parent {
+              [LegacyUnforgeable] undefined foo();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should have thrown when shadowing unforgeable operation on "
+        "parent with operation.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+              attribute short foo;
+            };
+            interface Parent {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should have thrown when shadowing unforgeable attribute on "
+        "parent with attribute.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+              attribute short foo;
+            };
+            interface Parent {
+              [LegacyUnforgeable] undefined foo();
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+    harness.ok(
+        threw,
+        "Should have thrown when shadowing unforgeable operation on "
+        "parent with attribute.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+            interface Child : Parent {
+            };
+            interface Parent {};
+            interface mixin Mixin {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+            Parent includes Mixin;
+        """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results),
+        4,
+        "Should be able to inherit from an interface with a "
+        "mixin with [LegacyUnforgeable] properties.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+              undefined foo();
+            };
+            interface Parent {};
+            interface mixin Mixin {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+            Parent includes Mixin;
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown when shadowing unforgeable attribute "
+        "of parent's consequential interface.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+            };
+            interface Parent : GrandParent {};
+            interface GrandParent {};
+            interface mixin Mixin {
+              [LegacyUnforgeable] readonly attribute long foo;
+            };
+            GrandParent includes Mixin;
+            interface mixin ChildMixin {
+              undefined foo();
+            };
+            Child includes ChildMixin;
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown when our consequential interface shadows unforgeable attribute "
+        "of ancestor's consequential interface.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface Child : Parent {
+            };
+            interface Parent : GrandParent {};
+            interface GrandParent {};
+            interface mixin Mixin {
+              [LegacyUnforgeable] undefined foo();
+            };
+            GrandParent includes Mixin;
+            interface mixin ChildMixin {
+              undefined foo();
+            };
+            Child includes ChildMixin;
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown when our consequential interface shadows unforgeable operation "
+        "of ancestor's consequential interface.",
+    )
+
+    parser = parser.reset()
+    parser.parse(
+        """
+        interface iface {
+          [LegacyUnforgeable] attribute long foo;
+        };
+    """
+    )
+
+    results = parser.finish()
+    harness.check(
+        len(results), 1, "Should allow writable [LegacyUnforgeable] attribute."
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface iface {
+              [LegacyUnforgeable] static readonly attribute long foo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown for static [LegacyUnforgeable] attribute.")
diff --git a/dom/bindings/parser/tests/test_union.py b/dom/bindings/parser/tests/test_union.py
new file mode 100644
index 0000000000..71791207ba
--- /dev/null
+++ b/dom/bindings/parser/tests/test_union.py
@@ -0,0 +1,198 @@
+import string
+
+import WebIDL
+
+# We'd like to use itertools.chain but it's 2.6 or higher.
+
+
+def chain(*iterables):
+    # chain('ABC', 'DEF') --> A B C D E F
+    for it in iterables:
+        for element in it:
+            yield element
+
+
+# We'd like to use itertools.combinations but it's 2.6 or higher.
+def combinations(iterable, r):
+    # combinations('ABCD', 2) --> AB AC AD BC BD CD
+    # combinations(range(4), 3) --> 012 013 023 123
+    pool = tuple(iterable)
+    n = len(pool)
+    if r > n:
+        return
+    indices = list(range(r))
+    yield tuple(pool[i] for i in indices)
+    while True:
+        for i in reversed(range(r)):
+            if indices[i] != i + n - r:
+                break
+        else:
+            return
+        indices[i] += 1
+        for j in range(i + 1, r):
+            indices[j] = indices[j - 1] + 1
+        yield tuple(pool[i] for i in indices)
+
+
+# We'd like to use itertools.combinations_with_replacement but it's 2.7 or
+# higher.
+def combinations_with_replacement(iterable, r):
+    # combinations_with_replacement('ABC', 2) --> AA AB AC BB BC CC
+    pool = tuple(iterable)
+    n = len(pool)
+    if not n and r:
+        return
+    indices = [0] * r
+    yield tuple(pool[i] for i in indices)
+    while True:
+        for i in reversed(range(r)):
+            if indices[i] != n - 1:
+                break
+        else:
+            return
+        indices[i:] = [indices[i] + 1] * (r - i)
+        yield tuple(pool[i] for i in indices)
+
+
+def WebIDLTest(parser, harness):
+    types = [
+        "float",
+        "double",
+        "short",
+        "unsigned short",
+        "long",
+        "unsigned long",
+        "long long",
+        "unsigned long long",
+        "boolean",
+        "byte",
+        "octet",
+        "DOMString",
+        "ByteString",
+        "USVString",
+        # "sequence<float>",
+        "object",
+        "ArrayBuffer",
+        # "Date",
+        "TestInterface1",
+        "TestInterface2",
+    ]
+
+    testPre = """
+        interface TestInterface1 {
+        };
+        interface TestInterface2 {
+        };
+        """
+
+    interface = (
+        testPre
+        + """
+        interface PrepareForTest {
+        """
+    )
+    for i, type in enumerate(types):
+        interface += string.Template(
+            """
+          readonly attribute ${type} attr${i};
+        """
+        ).substitute(i=i, type=type)
+    interface += """
+        };
+        """
+
+    parser.parse(interface)
+    results = parser.finish()
+
+    iface = results[2]
+
+    parser = parser.reset()
+
+    def typesAreDistinguishable(t):
+        return all(u[0].isDistinguishableFrom(u[1]) for u in combinations(t, 2))
+
+    def typesAreNotDistinguishable(t):
+        return any(not u[0].isDistinguishableFrom(u[1]) for u in combinations(t, 2))
+
+    def unionTypeName(t):
+        if len(t) > 2:
+            t[0:2] = [unionTypeName(t[0:2])]
+        return "(" + " or ".join(t) + ")"
+
+    # typeCombinations is an iterable of tuples containing the name of the type
+    # as a string and the parsed IDL type.
+    def unionTypes(typeCombinations, predicate):
+        for c in typeCombinations:
+            if predicate(t[1] for t in c):
+                yield unionTypeName([t[0] for t in c])
+
+    # We limit invalid union types with a union member type to the subset of 3
+    # types with one invalid combination.
+    # typeCombinations is an iterable of tuples containing the name of the type
+    # as a string and the parsed IDL type.
+    def invalidUnionWithUnion(typeCombinations):
+        for c in typeCombinations:
+            if (
+                typesAreNotDistinguishable((c[0][1], c[1][1]))
+                and typesAreDistinguishable((c[1][1], c[2][1]))
+                and typesAreDistinguishable((c[0][1], c[2][1]))
+            ):
+                yield unionTypeName([t[0] for t in c])
+
+    # Create a list of tuples containing the name of the type as a string and
+    # the parsed IDL type.
+    types = zip(types, (a.type for a in iface.members))
+
+    validUnionTypes = chain(
+        unionTypes(combinations(types, 2), typesAreDistinguishable),
+        unionTypes(combinations(types, 3), typesAreDistinguishable),
+    )
+    invalidUnionTypes = chain(
+        unionTypes(combinations_with_replacement(types, 2), typesAreNotDistinguishable),
+        invalidUnionWithUnion(combinations(types, 3)),
+    )
+    interface = (
+        testPre
+        + """
+        interface TestUnion {
+        """
+    )
+    for i, type in enumerate(validUnionTypes):
+        interface += string.Template(
+            """
+          undefined method${i}(${type} arg);
+          ${type} returnMethod${i}();
+          attribute ${type} attr${i};
+          undefined optionalMethod${i}(${type}? arg);
+        """
+        ).substitute(i=i, type=type)
+    interface += """
+        };
+        """
+    parser.parse(interface)
+    results = parser.finish()
+
+    parser = parser.reset()
+
+    for invalid in invalidUnionTypes:
+        interface = (
+            testPre
+            + string.Template(
+                """
+            interface TestUnion {
+              undefined method(${type} arg);
+            };
+        """
+            ).substitute(type=invalid)
+        )
+
+        threw = False
+        try:
+            parser.parse(interface)
+            results = parser.finish()
+        except WebIDL.WebIDLError:
+            threw = True
+
+        harness.ok(threw, "Should have thrown.")
+
+        parser = parser.reset()
diff --git a/dom/bindings/parser/tests/test_union_any.py b/dom/bindings/parser/tests/test_union_any.py
new file mode 100644
index 0000000000..7bde16a622
--- /dev/null
+++ b/dom/bindings/parser/tests/test_union_any.py
@@ -0,0 +1,19 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface AnyNotInUnion {
+              undefined foo((any or DOMString) arg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")
diff --git a/dom/bindings/parser/tests/test_union_nullable.py b/dom/bindings/parser/tests/test_union_nullable.py
new file mode 100644
index 0000000000..d5ae2e1e74
--- /dev/null
+++ b/dom/bindings/parser/tests/test_union_nullable.py
@@ -0,0 +1,63 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface OneNullableInUnion {
+              undefined foo((object? or DOMString?) arg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Two nullable member types of a union should have thrown.")
+
+    parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface NullableInNullableUnion {
+              undefined foo((object? or DOMString)? arg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "A nullable union type with a nullable member type should have " "thrown.",
+    )
+
+    parser.reset()
+    threw = False
+
+    try:
+        parser.parse(
+            """
+            interface NullableInUnionNullableUnionHelper {
+            };
+            interface NullableInUnionNullableUnion {
+              undefined foo(((object? or DOMString) or NullableInUnionNullableUnionHelper)? arg);
+            };
+        """
+        )
+
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "A nullable union type with a nullable member type should have " "thrown.",
+    )
diff --git a/dom/bindings/parser/tests/test_usvstring.py b/dom/bindings/parser/tests/test_usvstring.py
new file mode 100644
index 0000000000..effede391c
--- /dev/null
+++ b/dom/bindings/parser/tests/test_usvstring.py
@@ -0,0 +1,40 @@
+# -*- coding: UTF-8 -*-
+
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface TestUSVString {
+          attribute USVString svs;
+        };
+    """
+    )
+
+    results = parser.finish()
+
+    harness.check(len(results), 1, "Should be one production")
+    harness.ok(isinstance(results[0], WebIDL.IDLInterface), "Should be an IDLInterface")
+    iface = results[0]
+    harness.check(
+        iface.identifier.QName(), "::TestUSVString", "Interface has the right QName"
+    )
+    harness.check(
+        iface.identifier.name, "TestUSVString", "Interface has the right name"
+    )
+    harness.check(iface.parent, None, "Interface has no parent")
+
+    members = iface.members
+    harness.check(len(members), 1, "Should be one member")
+
+    attr = members[0]
+    harness.ok(isinstance(attr, WebIDL.IDLAttribute), "Should be an IDLAttribute")
+    harness.check(
+        attr.identifier.QName(), "::TestUSVString::svs", "Attr has correct QName"
+    )
+    harness.check(attr.identifier.name, "svs", "Attr has correct name")
+    harness.check(str(attr.type), "USVString", "Attr type is the correct name")
+    harness.ok(attr.type.isUSVString(), "Should be USVString type")
+    harness.ok(attr.type.isString(), "Should be String collective type")
+    harness.ok(not attr.type.isDOMString(), "Should be not be DOMString type")
diff --git a/dom/bindings/parser/tests/test_variadic_callback.py b/dom/bindings/parser/tests/test_variadic_callback.py
new file mode 100644
index 0000000000..fab1c7ef10
--- /dev/null
+++ b/dom/bindings/parser/tests/test_variadic_callback.py
@@ -0,0 +1,10 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        callback TestVariadicCallback = any(any... arguments);
+    """
+    )
+
+    parser.finish()
+
+    harness.ok(True, "TestVariadicCallback callback parsed without error.")
diff --git a/dom/bindings/parser/tests/test_variadic_constraints.py b/dom/bindings/parser/tests/test_variadic_constraints.py
new file mode 100644
index 0000000000..749c4a7812
--- /dev/null
+++ b/dom/bindings/parser/tests/test_variadic_constraints.py
@@ -0,0 +1,77 @@
+import WebIDL
+
+
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface VariadicConstraints1 {
+              undefined foo(byte... arg1, byte arg2);
+            };
+        """
+        )
+        parser.finish()
+
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown on variadic argument followed by required " "argument.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface VariadicConstraints2 {
+              undefined foo(byte... arg1, optional byte arg2);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown on variadic argument followed by optional " "argument.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface VariadicConstraints3 {
+              undefined foo(optional byte... arg1);
+            };
+        """
+        )
+        parser.finish()
+
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(
+        threw,
+        "Should have thrown on variadic argument explicitly flagged as " "optional.",
+    )
+
+    parser = parser.reset()
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface VariadicConstraints4 {
+              undefined foo(byte... arg1 = 0);
+            };
+        """
+        )
+        parser.finish()
+    except WebIDL.WebIDLError:
+        threw = True
+
+    harness.ok(threw, "Should have thrown on variadic argument with default value.")