1 files changed, 49 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/transform-streams/properties.any.js b/testing/web-platform/tests/streams/transform-streams/properties.any.js
new file mode 100644
index 0000000000..02981b8bc7
--- /dev/null
+++ b/testing/web-platform/tests/streams/transform-streams/properties.any.js
@@ -0,0 +1,49 @@
+// META: global=window,worker
+'use strict';
+
+const transformerMethods = {
+  start: {
+    length: 1,
+    trigger: () => Promise.resolve()
+  },
+  transform: {
+    length: 2,
+    trigger: ts => ts.writable.getWriter().write()
+  },
+  flush: {
+    length: 1,
+    trigger: ts => ts.writable.getWriter().close()
+  }
+};
+
+for (const method in transformerMethods) {
+  const { length, trigger } = transformerMethods[method];
+
+  // Some semantic tests of how transformer methods are called can be found in general.js, as well as in the test files
+  // specific to each method.
+  promise_test(() => {
+    let argCount;
+    const ts = new TransformStream({
+      [method](...args) {
+        argCount = args.length;
+      }
+    }, undefined, { highWaterMark: Infinity });
+    return Promise.resolve(trigger(ts)).then(() => {
+      assert_equals(argCount, length, `${method} should be called with ${length} arguments`);
+    });
+  }, `transformer method ${method} should be called with the right number of arguments`);
+
+  promise_test(() => {
+    let methodWasCalled = false;
+    function Transformer() {}
+    Transformer.prototype = {
+      [method]() {
+        methodWasCalled = true;
+      }
+    };
+    const ts = new TransformStream(new Transformer(), undefined, { highWaterMark: Infinity });
+    return Promise.resolve(trigger(ts)).then(() => {
+      assert_true(methodWasCalled, `${method} should be called`);
+    });
+  }, `transformer method ${method} should be called even when it's located on the prototype chain`);
+}