2 files changed, 563 insertions, 0 deletions
diff --git a/cli/js/tests/streams_transform_test.ts b/cli/js/tests/streams_transform_test.ts
new file mode 100644
index 000000000..f3ec148ae
--- /dev/null
+++ b/cli/js/tests/streams_transform_test.ts
@@ -0,0 +1,562 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import {
+  unitTest,
+  assert,
+  assertEquals,
+  assertNotEquals,
+  assertThrows,
+} from "./test_util.ts";
+
+function delay(seconds: number): Promise<void> {
+  return new Promise<void>((resolve) => {
+    setTimeout(() => {
+      resolve();
+    }, seconds);
+  });
+}
+
+function readableStreamToArray<R>(
+  readable: { getReader(): ReadableStreamDefaultReader<R> },
+  reader?: ReadableStreamDefaultReader<R>
+): Promise<R[]> {
+  if (reader === undefined) {
+    reader = readable.getReader();
+  }
+
+  const chunks: R[] = [];
+
+  return pump();
+
+  function pump(): Promise<R[]> {
+    return reader!.read().then((result) => {
+      if (result.done) {
+        return chunks;
+      }
+
+      chunks.push(result.value);
+      return pump();
+    });
+  }
+}
+
+unitTest(function transformStreamConstructedWithTransformFunction() {
+  new TransformStream({ transform(): void {} });
+});
+
+unitTest(function transformStreamConstructedNoTransform() {
+  new TransformStream();
+  new TransformStream({});
+});
+
+unitTest(function transformStreamIntstancesHaveProperProperties() {
+  const ts = new TransformStream({ transform(): void {} });
+  const proto = Object.getPrototypeOf(ts);
+
+  const writableStream = Object.getOwnPropertyDescriptor(proto, "writable");
+  assert(writableStream !== undefined, "it has a writable property");
+  assert(!writableStream.enumerable, "writable should be non-enumerable");
+  assertEquals(
+    typeof writableStream.get,
+    "function",
+    "writable should have a getter"
+  );
+  assertEquals(
+    writableStream.set,
+    undefined,
+    "writable should not have a setter"
+  );
+  assert(writableStream.configurable, "writable should be configurable");
+  assert(
+    ts.writable instanceof WritableStream,
+    "writable is an instance of WritableStream"
+  );
+  assert(
+    WritableStream.prototype.getWriter.call(ts.writable),
+    "writable should pass WritableStream brand check"
+  );
+
+  const readableStream = Object.getOwnPropertyDescriptor(proto, "readable");
+  assert(readableStream !== undefined, "it has a readable property");
+  assert(!readableStream.enumerable, "readable should be non-enumerable");
+  assertEquals(
+    typeof readableStream.get,
+    "function",
+    "readable should have a getter"
+  );
+  assertEquals(
+    readableStream.set,
+    undefined,
+    "readable should not have a setter"
+  );
+  assert(readableStream.configurable, "readable should be configurable");
+  assert(
+    ts.readable instanceof ReadableStream,
+    "readable is an instance of ReadableStream"
+  );
+  assertNotEquals(
+    ReadableStream.prototype.getReader.call(ts.readable),
+    undefined,
+    "readable should pass ReadableStream brand check"
+  );
+});
+
+unitTest(function transformStreamWritableStartsAsWritable() {
+  const ts = new TransformStream({ transform(): void {} });
+
+  const writer = ts.writable.getWriter();
+  assertEquals(writer.desiredSize, 1, "writer.desiredSize should be 1");
+});
+
+unitTest(async function transformStreamReadableCanReadOutOfWritable() {
+  const ts = new TransformStream();
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  assertEquals(
+    writer.desiredSize,
+    0,
+    "writer.desiredSize should be 0 after write()"
+  );
+
+  const result = await ts.readable.getReader().read();
+  assertEquals(
+    result.value,
+    "a",
+    "result from reading the readable is the same as was written to writable"
+  );
+  assert(!result.done, "stream should not be done");
+
+  await delay(0);
+  assert(writer.desiredSize === 1, "desiredSize should be 1 again");
+});
+
+unitTest(async function transformStreamCanReadWhatIsWritten() {
+  let c: TransformStreamDefaultController;
+  const ts = new TransformStream({
+    start(controller: TransformStreamDefaultController): void {
+      c = controller;
+    },
+    transform(chunk: string): void {
+      c.enqueue(chunk.toUpperCase());
+    },
+  });
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+
+  const result = await ts.readable.getReader().read();
+  assertEquals(
+    result.value,
+    "A",
+    "result from reading the readable is the transformation of what was written to writable"
+  );
+  assert(!result.done, "stream should not be done");
+});
+
+unitTest(async function transformStreamCanReadBothChunks() {
+  let c: TransformStreamDefaultController;
+  const ts = new TransformStream({
+    start(controller: TransformStreamDefaultController): void {
+      c = controller;
+    },
+    transform(chunk: string): void {
+      c.enqueue(chunk.toUpperCase());
+      c.enqueue(chunk.toUpperCase());
+    },
+  });
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+
+  const reader = ts.readable.getReader();
+
+  const result1 = await reader.read();
+  assertEquals(
+    result1.value,
+    "A",
+    "the first chunk read is the transformation of the single chunk written"
+  );
+  assert(!result1.done, "stream should not be done");
+
+  const result2 = await reader.read();
+  assertEquals(
+    result2.value,
+    "A",
+    "the second chunk read is also the transformation of the single chunk written"
+  );
+  assert(!result2.done, "stream should not be done");
+});
+
+unitTest(async function transformStreamCanReadWhatIsWritten() {
+  let c: TransformStreamDefaultController;
+  const ts = new TransformStream({
+    start(controller: TransformStreamDefaultController): void {
+      c = controller;
+    },
+    transform(chunk: string): Promise<void> {
+      return delay(0).then(() => c.enqueue(chunk.toUpperCase()));
+    },
+  });
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+
+  const result = await ts.readable.getReader().read();
+  assertEquals(
+    result.value,
+    "A",
+    "result from reading the readable is the transformation of what was written to writable"
+  );
+  assert(!result.done, "stream should not be done");
+});
+
+unitTest(async function transformStreamAsyncReadMultipleChunks() {
+  let doSecondEnqueue: () => void;
+  let returnFromTransform: () => void;
+  const ts = new TransformStream({
+    transform(
+      chunk: string,
+      controller: TransformStreamDefaultController
+    ): Promise<void> {
+      delay(0).then(() => controller.enqueue(chunk.toUpperCase()));
+      doSecondEnqueue = (): void => controller.enqueue(chunk.toUpperCase());
+      return new Promise((resolve) => {
+        returnFromTransform = resolve;
+      });
+    },
+  });
+
+  const reader = ts.readable.getReader();
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+
+  const result1 = await reader.read();
+  assertEquals(
+    result1.value,
+    "A",
+    "the first chunk read is the transformation of the single chunk written"
+  );
+  assert(!result1.done, "stream should not be done");
+  doSecondEnqueue!();
+
+  const result2 = await reader.read();
+  assertEquals(
+    result2.value,
+    "A",
+    "the second chunk read is also the transformation of the single chunk written"
+  );
+  assert(!result2.done, "stream should not be done");
+  returnFromTransform!();
+});
+
+unitTest(function transformStreamClosingWriteClosesRead() {
+  const ts = new TransformStream({ transform(): void {} });
+
+  const writer = ts.writable.getWriter();
+  writer.close();
+
+  return Promise.all([writer.closed, ts.readable.getReader().closed]).then(
+    undefined
+  );
+});
+
+unitTest(async function transformStreamCloseWaitAwaitsTransforms() {
+  let transformResolve: () => void;
+  const transformPromise = new Promise<void>((resolve) => {
+    transformResolve = resolve;
+  });
+  const ts = new TransformStream(
+    {
+      transform(): Promise<void> {
+        return transformPromise;
+      },
+    },
+    undefined,
+    { highWaterMark: 1 }
+  );
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  writer.close();
+
+  let rsClosed = false;
+  ts.readable.getReader().closed.then(() => {
+    rsClosed = true;
+  });
+
+  await delay(0);
+  assertEquals(rsClosed, false, "readable is not closed after a tick");
+  transformResolve!();
+
+  await writer.closed;
+  // TODO: Is this expectation correct?
+  assertEquals(rsClosed, true, "readable is closed at that point");
+});
+
+unitTest(async function transformStreamCloseWriteAfterSyncEnqueues() {
+  let c: TransformStreamDefaultController<string>;
+  const ts = new TransformStream<string, string>({
+    start(controller: TransformStreamDefaultController): void {
+      c = controller;
+    },
+    transform(): Promise<void> {
+      c.enqueue("x");
+      c.enqueue("y");
+      return delay(0);
+    },
+  });
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  writer.close();
+
+  const readableChunks = readableStreamToArray(ts.readable);
+
+  await writer.closed;
+  const chunks = await readableChunks;
+  assertEquals(
+    chunks,
+    ["x", "y"],
+    "both enqueued chunks can be read from the readable"
+  );
+});
+
+unitTest(async function transformStreamWritableCloseAsyncAfterAsyncEnqueues() {
+  let c: TransformStreamDefaultController<string>;
+  const ts = new TransformStream<string, string>({
+    start(controller: TransformStreamDefaultController<string>): void {
+      c = controller;
+    },
+    transform(): Promise<void> {
+      return delay(0)
+        .then(() => c.enqueue("x"))
+        .then(() => c.enqueue("y"))
+        .then(() => delay(0));
+    },
+  });
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  writer.close();
+
+  const readableChunks = readableStreamToArray(ts.readable);
+
+  await writer.closed;
+  const chunks = await readableChunks;
+  assertEquals(
+    chunks,
+    ["x", "y"],
+    "both enqueued chunks can be read from the readable"
+  );
+});
+
+unitTest(async function transformStreamTransformerMethodsCalledAsMethods() {
+  let c: TransformStreamDefaultController<string>;
+  const transformer = {
+    suffix: "-suffix",
+
+    start(controller: TransformStreamDefaultController<string>): void {
+      c = controller;
+      c.enqueue("start" + this.suffix);
+    },
+
+    transform(chunk: string): void {
+      c.enqueue(chunk + this.suffix);
+    },
+
+    flush(): void {
+      c.enqueue("flushed" + this.suffix);
+    },
+  };
+  const ts = new TransformStream(transformer);
+
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  writer.close();
+
+  const readableChunks = readableStreamToArray(ts.readable);
+
+  await writer.closed;
+  const chunks = await readableChunks;
+  assertEquals(
+    chunks,
+    ["start-suffix", "a-suffix", "flushed-suffix"],
+    "all enqueued chunks have suffixes"
+  );
+});
+
+unitTest(async function transformStreamMethodsShouldNotBeAppliedOrCalled() {
+  function functionWithOverloads(): void {}
+  functionWithOverloads.apply = (): void => {
+    throw new Error("apply() should not be called");
+  };
+  functionWithOverloads.call = (): void => {
+    throw new Error("call() should not be called");
+  };
+  const ts = new TransformStream({
+    start: functionWithOverloads,
+    transform: functionWithOverloads,
+    flush: functionWithOverloads,
+  });
+  const writer = ts.writable.getWriter();
+  writer.write("a");
+  writer.close();
+
+  await readableStreamToArray(ts.readable);
+});
+
+unitTest(async function transformStreamCallTransformSync() {
+  let transformCalled = false;
+  const ts = new TransformStream(
+    {
+      transform(): void {
+        transformCalled = true;
+      },
+    },
+    undefined,
+    { highWaterMark: Infinity }
+  );
+  // transform() is only called synchronously when there is no backpressure and
+  // all microtasks have run.
+  await delay(0);
+  const writePromise = ts.writable.getWriter().write(undefined);
+  assert(transformCalled, "transform() should have been called");
+  await writePromise;
+});
+
+unitTest(function transformStreamCloseWriteCloesesReadWithNoChunks() {
+  const ts = new TransformStream({}, undefined, { highWaterMark: 0 });
+
+  const writer = ts.writable.getWriter();
+  writer.close();
+
+  return Promise.all([writer.closed, ts.readable.getReader().closed]).then(
+    undefined
+  );
+});
+
+unitTest(function transformStreamEnqueueThrowsAfterTerminate() {
+  new TransformStream({
+    start(controller: TransformStreamDefaultController): void {
+      controller.terminate();
+      assertThrows(() => {
+        controller.enqueue(undefined);
+      }, TypeError);
+    },
+  });
+});
+
+unitTest(function transformStreamEnqueueThrowsAfterReadableCancel() {
+  let controller: TransformStreamDefaultController;
+  const ts = new TransformStream({
+    start(c: TransformStreamDefaultController): void {
+      controller = c;
+    },
+  });
+  const cancelPromise = ts.readable.cancel();
+  assertThrows(
+    () => controller.enqueue(undefined),
+    TypeError,
+    undefined,
+    "enqueue should throw"
+  );
+  return cancelPromise;
+});
+
+unitTest(function transformStreamSecondTerminateNoOp() {
+  new TransformStream({
+    start(controller: TransformStreamDefaultController): void {
+      controller.terminate();
+      controller.terminate();
+    },
+  });
+});
+
+unitTest(async function transformStreamTerminateAfterReadableCancelIsNoop() {
+  let controller: TransformStreamDefaultController;
+  const ts = new TransformStream({
+    start(c: TransformStreamDefaultController): void {
+      controller = c;
+    },
+  });
+  const cancelReason = { name: "cancelReason" };
+  const cancelPromise = ts.readable.cancel(cancelReason);
+  controller!.terminate();
+  await cancelPromise;
+  try {
+    await ts.writable.getWriter().closed;
+  } catch (e) {
+    assert(e === cancelReason);
+    return;
+  }
+  throw new Error("closed should have rejected");
+});
+
+unitTest(async function transformStreamStartCalledOnce() {
+  let calls = 0;
+  new TransformStream({
+    start(): void {
+      ++calls;
+    },
+  });
+  await delay(0);
+  assertEquals(calls, 1, "start() should have been called exactly once");
+});
+
+unitTest(function transformStreamReadableTypeThrows() {
+  assertThrows(
+    // eslint-disable-next-line
+    () => new TransformStream({ readableType: "bytes" as any }),
+    RangeError,
+    undefined,
+    "constructor should throw"
+  );
+});
+
+unitTest(function transformStreamWirtableTypeThrows() {
+  assertThrows(
+    // eslint-disable-next-line
+    () => new TransformStream({ writableType: "bytes" as any }),
+    RangeError,
+    undefined,
+    "constructor should throw"
+  );
+});
+
+unitTest(function transformStreamSubclassable() {
+  class Subclass extends TransformStream {
+    extraFunction(): boolean {
+      return true;
+    }
+  }
+  assert(
+    Object.getPrototypeOf(Subclass.prototype) === TransformStream.prototype,
+    "Subclass.prototype's prototype should be TransformStream.prototype"
+  );
+  assert(
+    Object.getPrototypeOf(Subclass) === TransformStream,
+    "Subclass's prototype should be TransformStream"
+  );
+  const sub = new Subclass();
+  assert(
+    sub instanceof TransformStream,
+    "Subclass object should be an instance of TransformStream"
+  );
+  assert(
+    sub instanceof Subclass,
+    "Subclass object should be an instance of Subclass"
+  );
+  const readableGetter = Object.getOwnPropertyDescriptor(
+    TransformStream.prototype,
+    "readable"
+  )!.get;
+  assert(
+    readableGetter!.call(sub) === sub.readable,
+    "Subclass object should pass brand check"
+  );
+  assert(
+    sub.extraFunction(),
+    "extraFunction() should be present on Subclass object"
+  );
+});
diff --git a/cli/js/tests/unit_tests.ts b/cli/js/tests/unit_tests.ts
index 40d0124d3..7327bcc05 100644
--- a/cli/js/tests/unit_tests.ts
+++ b/cli/js/tests/unit_tests.ts
@@ -53,6 +53,7 @@ import "./resources_test.ts";
 import "./signal_test.ts";
 import "./stat_test.ts";
 import "./streams_piping_test.ts";
+import "./streams_transform_test.ts";
 import "./streams_writable_test.ts";
 import "./symlink_test.ts";
 import "./text_encoding_test.ts";