1 files changed, 150 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/transform-streams/strategies.any.js b/testing/web-platform/tests/streams/transform-streams/strategies.any.js
new file mode 100644
index 0000000000..57e113e668
--- /dev/null
+++ b/testing/web-platform/tests/streams/transform-streams/strategies.any.js
@@ -0,0 +1,150 @@
+// META: global=window,worker,shadowrealm
+// META: script=../resources/recording-streams.js
+// META: script=../resources/test-utils.js
+'use strict';
+
+// Here we just test that the strategies are correctly passed to the readable and writable sides. We assume that
+// ReadableStream and WritableStream will correctly apply the strategies when they are being used by a TransformStream
+// and so it isn't necessary to repeat their tests here.
+
+test(() => {
+  const ts = new TransformStream({}, { highWaterMark: 17 });
+  assert_equals(ts.writable.getWriter().desiredSize, 17, 'desiredSize should be 17');
+}, 'writableStrategy highWaterMark should work');
+
+promise_test(() => {
+  const ts = recordingTransformStream({}, undefined, { highWaterMark: 9 });
+  const writer = ts.writable.getWriter();
+  for (let i = 0; i < 10; ++i) {
+    writer.write(i);
+  }
+  return delay(0).then(() => {
+    assert_array_equals(ts.events, [
+      'transform', 0, 'transform', 1, 'transform', 2, 'transform', 3, 'transform', 4,
+      'transform', 5, 'transform', 6, 'transform', 7, 'transform', 8],
+                        'transform() should have been called 9 times');
+  });
+}, 'readableStrategy highWaterMark should work');
+
+promise_test(t => {
+  let writableSizeCalled = false;
+  let readableSizeCalled = false;
+  let transformCalled = false;
+  const ts = new TransformStream(
+    {
+      transform(chunk, controller) {
+        t.step(() => {
+          transformCalled = true;
+          assert_true(writableSizeCalled, 'writableStrategy.size() should have been called');
+          assert_false(readableSizeCalled, 'readableStrategy.size() should not have been called');
+          controller.enqueue(chunk);
+          assert_true(readableSizeCalled, 'readableStrategy.size() should have been called');
+        });
+      }
+    },
+    {
+      size() {
+        writableSizeCalled = true;
+        return 1;
+      }
+    },
+    {
+      size() {
+        readableSizeCalled = true;
+        return 1;
+      },
+      highWaterMark: Infinity
+    });
+  return ts.writable.getWriter().write().then(() => {
+    assert_true(transformCalled, 'transform() should be called');
+  });
+}, 'writable should have the correct size() function');
+
+test(() => {
+  const ts = new TransformStream();
+  const writer = ts.writable.getWriter();
+  assert_equals(writer.desiredSize, 1, 'default writable HWM is 1');
+  writer.write(undefined);
+  assert_equals(writer.desiredSize, 0, 'default chunk size is 1');
+}, 'default writable strategy should be equivalent to { highWaterMark: 1 }');
+
+promise_test(t => {
+  const ts = new TransformStream({
+    transform(chunk, controller) {
+      return t.step(() => {
+        assert_equals(controller.desiredSize, 0, 'desiredSize should be 0');
+        controller.enqueue(undefined);
+        // The first chunk enqueued is consumed by the pending read().
+        assert_equals(controller.desiredSize, 0, 'desiredSize should still be 0');
+        controller.enqueue(undefined);
+        assert_equals(controller.desiredSize, -1, 'desiredSize should be -1');
+      });
+    }
+  });
+  const writePromise = ts.writable.getWriter().write();
+  return ts.readable.getReader().read().then(() => writePromise);
+}, 'default readable strategy should be equivalent to { highWaterMark: 0 }');
+
+test(() => {
+  assert_throws_js(RangeError, () => new TransformStream(undefined, { highWaterMark: -1 }),
+                   'should throw RangeError for negative writableHighWaterMark');
+  assert_throws_js(RangeError, () => new TransformStream(undefined, undefined, { highWaterMark: -1 }),
+                   'should throw RangeError for negative readableHighWaterMark');
+  assert_throws_js(RangeError, () => new TransformStream(undefined, { highWaterMark: NaN }),
+                   'should throw RangeError for NaN writableHighWaterMark');
+  assert_throws_js(RangeError, () => new TransformStream(undefined, undefined, { highWaterMark: NaN }),
+                   'should throw RangeError for NaN readableHighWaterMark');
+}, 'a RangeError should be thrown for an invalid highWaterMark');
+
+const objectThatConvertsTo42 = {
+  toString() {
+    return '42';
+  }
+};
+
+test(() => {
+  const ts = new TransformStream(undefined, { highWaterMark: objectThatConvertsTo42 });
+  const writer = ts.writable.getWriter();
+  assert_equals(writer.desiredSize, 42, 'writable HWM is 42');
+}, 'writableStrategy highWaterMark should be converted to a number');
+
+test(() => {
+  const ts = new TransformStream({
+    start(controller) {
+      assert_equals(controller.desiredSize, 42, 'desiredSize should be 42');
+    }
+  }, undefined, { highWaterMark: objectThatConvertsTo42 });
+}, 'readableStrategy highWaterMark should be converted to a number');
+
+promise_test(t => {
+  const ts = new TransformStream(undefined, undefined, {
+    size() { return NaN; },
+    highWaterMark: 1
+  });
+  const writer = ts.writable.getWriter();
+  return promise_rejects_js(t, RangeError, writer.write(), 'write should reject');
+}, 'a bad readableStrategy size function should cause writer.write() to reject on an identity transform');
+
+promise_test(t => {
+  const ts = new TransformStream({
+    transform(chunk, controller) {
+      // This assert has the important side-effect of catching the error, so transform() does not throw.
+      assert_throws_js(RangeError, () => controller.enqueue(chunk), 'enqueue should throw');
+    }
+  }, undefined, {
+    size() {
+      return -1;
+    },
+    highWaterMark: 1
+  });
+
+  const writer = ts.writable.getWriter();
+  return writer.write().then(() => {
+    return Promise.all([
+      promise_rejects_js(t, RangeError, writer.ready, 'ready should reject'),
+      promise_rejects_js(t, RangeError, writer.closed, 'closed should reject'),
+      promise_rejects_js(t, RangeError, ts.readable.getReader().closed, 'readable closed should reject')
+    ]);
+  });
+}, 'a bad readableStrategy size function should error the stream on enqueue even when transformer.transform() ' +
+   'catches the exception');