1 files changed, 115 insertions, 0 deletions
diff --git a/js/xpconnect/tests/unit/test_defineModuleGetter.js b/js/xpconnect/tests/unit/test_defineModuleGetter.js
new file mode 100644
index 0000000000..34acceb853
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_defineModuleGetter.js
@@ -0,0 +1,115 @@
+"use strict";
+
+function assertIsGetter(obj, prop) {
+  let desc = Object.getOwnPropertyDescriptor(obj, prop);
+
+  ok(desc, `Property ${prop} exists on object`);
+  equal(typeof desc.get, "function", `Getter function exists for property ${prop}`);
+  equal(typeof desc.set, "function", `Setter function exists for property ${prop}`);
+  equal(desc.enumerable, true, `Property ${prop} is enumerable`);
+  equal(desc.configurable, true, `Property ${prop} is configurable`);
+}
+
+function assertIsValue(obj, prop, value) {
+  let desc = Object.getOwnPropertyDescriptor(obj, prop);
+
+  ok(desc, `Property ${prop} exists on object`);
+
+  ok("value" in desc, `${prop} is a data property`);
+  equal(desc.value, value, `${prop} has the expected value`);
+
+  equal(desc.enumerable, true, `Property ${prop} is enumerable`);
+  equal(desc.configurable, true, `Property ${prop} is configurable`);
+  equal(desc.writable, true, `Property ${prop} is writable`);
+}
+
+add_task(async function() {
+  let temp = {};
+  ChromeUtils.import("resource://gre/modules/AppConstants.jsm", temp);
+
+  let obj = {};
+  let child = Object.create(obj);
+  let sealed = Object.seal(Object.create(obj));
+
+
+  // Test valid import
+
+  ChromeUtils.defineModuleGetter(obj, "AppConstants",
+                                 "resource://gre/modules/AppConstants.jsm");
+
+  assertIsGetter(obj, "AppConstants");
+  equal(child.AppConstants, temp.AppConstants, "Getter works on descendent object");
+  assertIsValue(child, "AppConstants", temp.AppConstants);
+  assertIsGetter(obj, "AppConstants");
+
+  Assert.throws(() => sealed.AppConstants, /Object is not extensible/,
+                "Cannot access lazy getter from sealed object");
+  Assert.throws(() => sealed.AppConstants = null, /Object is not extensible/,
+                "Cannot access lazy setter from sealed object");
+  assertIsGetter(obj, "AppConstants");
+
+  equal(obj.AppConstants, temp.AppConstants, "Getter works on object");
+  assertIsValue(obj, "AppConstants", temp.AppConstants);
+
+
+  // Test overwriting via setter
+
+  child = Object.create(obj);
+
+  ChromeUtils.defineModuleGetter(obj, "AppConstants",
+                                 "resource://gre/modules/AppConstants.jsm");
+
+  assertIsGetter(obj, "AppConstants");
+
+  child.AppConstants = "foo";
+  assertIsValue(child, "AppConstants", "foo");
+  assertIsGetter(obj, "AppConstants");
+
+  obj.AppConstants = "foo";
+  assertIsValue(obj, "AppConstants", "foo");
+
+
+  // Test import missing property
+
+  ChromeUtils.defineModuleGetter(obj, "meh",
+                                 "resource://gre/modules/AppConstants.jsm");
+  assertIsGetter(obj, "meh");
+  equal(obj.meh, undefined, "Missing property returns undefined");
+  assertIsValue(obj, "meh", undefined);
+
+
+  // Test import broken module
+
+  ChromeUtils.defineModuleGetter(obj, "broken",
+                                 "resource://test/bogus_exports_type.jsm");
+  assertIsGetter(obj, "broken");
+
+  let errorPattern = /EXPORTED_SYMBOLS is not an array/;
+  Assert.throws(() => child.broken, errorPattern,
+                "Broken import throws on child");
+  Assert.throws(() => child.broken, errorPattern,
+                "Broken import throws on child again");
+  Assert.throws(() => sealed.broken, errorPattern,
+                "Broken import throws on sealed child");
+  Assert.throws(() => obj.broken, errorPattern,
+                "Broken import throws on object");
+  assertIsGetter(obj, "broken");
+
+
+  // Test import missing module
+
+  ChromeUtils.defineModuleGetter(obj, "missing",
+                                 "resource://test/does_not_exist.jsm");
+  assertIsGetter(obj, "missing");
+
+  Assert.throws(() => obj.missing, /NS_ERROR_FILE_NOT_FOUND/,
+                "missing import throws on object");
+  assertIsGetter(obj, "missing");
+
+
+  // Test overwriting broken import via setter
+
+  assertIsGetter(obj, "broken");
+  obj.broken = "foo";
+  assertIsValue(obj, "broken", "foo");
+});