1 files changed, 108 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/transferable/transform-stream.html b/testing/web-platform/tests/streams/transferable/transform-stream.html
new file mode 100644
index 0000000000..355d5d8074
--- /dev/null
+++ b/testing/web-platform/tests/streams/transferable/transform-stream.html
@@ -0,0 +1,108 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/test-utils.js"></script>
+<script>
+'use strict';
+
+promise_test(t => {
+  const orig = new TransformStream();
+  const promise = new Promise(resolve => {
+    addEventListener('message', t.step_func(evt => {
+      const transferred = evt.data;
+      assert_equals(transferred.constructor, TransformStream,
+                    'transferred should be a TransformStream in this realm');
+      assert_true(transferred instanceof TransformStream,
+                  'instanceof check should pass');
+
+      // Perform a brand-check on |transferred|.
+      const readableGetter = Object.getOwnPropertyDescriptor(
+        TransformStream.prototype, 'readable').get;
+      assert_true(readableGetter.call(transferred) instanceof ReadableStream,
+                 'brand check should pass and readable stream should result');
+      const writableGetter = Object.getOwnPropertyDescriptor(
+        TransformStream.prototype, 'writable').get;
+      assert_true(writableGetter.call(transferred) instanceof WritableStream,
+                 'brand check should pass and writable stream should result');
+      resolve();
+    }), {once: true});
+  });
+  postMessage(orig, '*', [orig]);
+  assert_true(orig.readable.locked, 'the readable side should be locked');
+  assert_true(orig.writable.locked, 'the writable side should be locked');
+  return promise;
+}, 'window.postMessage should be able to transfer a TransformStream');
+
+test(() => {
+  const ts = new TransformStream();
+  const writer = ts.writable.getWriter();
+  assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
+                    'postMessage should throw');
+  assert_false(ts.readable.locked, 'readable side should not get locked');
+}, 'a TransformStream with a locked writable should not be transferable');
+
+test(() => {
+  const ts = new TransformStream();
+  const reader = ts.readable.getReader();
+  assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
+                    'postMessage should throw');
+  assert_false(ts.writable.locked, 'writable side should not get locked');
+}, 'a TransformStream with a locked readable should not be transferable');
+
+test(() => {
+  const ts = new TransformStream();
+  const reader = ts.readable.getReader();
+  const writer = ts.writable.getWriter();
+  assert_throws_dom('DataCloneError', () => postMessage(ts, '*', [ts]),
+                    'postMessage should throw');
+}, 'a TransformStream with both sides locked should not be transferable');
+
+promise_test(t => {
+  const source = new ReadableStream({
+    start(controller) {
+      controller.enqueue('hello ');
+      controller.enqueue('there ');
+      controller.close();
+    }
+  });
+  let resolve;
+  const ready = new Promise(r => resolve = r);
+  let result = '';
+  const sink = new WritableStream({
+    write(chunk) {
+      if (result) {
+        resolve();
+      }
+      result += chunk;
+    }
+  });
+  const transform1 = new TransformStream({
+    transform(chunk, controller) {
+      controller.enqueue(chunk.toUpperCase());
+    }
+  });
+  const transform2 = new TransformStream({
+    transform(chunk, controller) {
+      controller.enqueue(chunk + chunk);
+    }
+  });
+  const promise = new Promise(resolve => {
+    addEventListener('message', t.step_func(evt => {
+      const data = evt.data;
+      resolve(data.source
+                .pipeThrough(data.transform1)
+                .pipeThrough(data.transform2)
+                .pipeTo(data.sink));
+    }));
+  });
+  postMessage({source, sink, transform1, transform2}, '*',
+              [source, transform1, sink, transform2]);
+  return ready
+    .then(() => {
+      assert_equals(result, 'HELLO HELLO THERE THERE ',
+                    'transforms should have been applied');
+    });
+}, 'piping through transferred transforms should work');
+
+</script>