1 files changed, 108 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/readable-streams/pipe-through.js b/testing/web-platform/tests/streams/readable-streams/pipe-through.js
new file mode 100644
index 000000000..4988928e7
--- /dev/null
+++ b/testing/web-platform/tests/streams/readable-streams/pipe-through.js
@@ -0,0 +1,108 @@
+'use strict';
+
+if (self.importScripts) {
+  self.importScripts('../resources/test-utils.js');
+  self.importScripts('/resources/testharness.js');
+}
+
+test(() => {
+
+  let pipeToArguments;
+  const thisValue = {
+    pipeTo() {
+      pipeToArguments = arguments;
+    }
+  };
+
+  const input = { readable: {}, writable: {} };
+  const options = {};
+  const result = ReadableStream.prototype.pipeThrough.call(thisValue, input, options);
+
+  assert_array_equals(pipeToArguments, [input.writable, options],
+    'correct arguments should be passed to thisValue.pipeTo');
+  assert_equals(result, input.readable, 'return value should be the passed readable property');
+
+}, 'ReadableStream.prototype.pipeThrough should work generically on its this and its arguments');
+
+test(() => {
+
+  const thisValue = {
+    pipeTo() {
+      assert_unreached('pipeTo should not be called');
+    }
+  };
+
+  methodThrows(ReadableStream.prototype, 'pipeThrough', thisValue, [undefined, {}]);
+  methodThrows(ReadableStream.prototype, 'pipeThrough', thisValue, [null, {}]);
+
+}, 'ReadableStream.prototype.pipeThrough should throw when its first argument is not convertible to an object');
+
+test(() => {
+
+  const args = [{ readable: {}, writable: {} }, {}];
+
+  methodThrows(ReadableStream.prototype, 'pipeThrough', undefined, args);
+  methodThrows(ReadableStream.prototype, 'pipeThrough', null, args);
+  methodThrows(ReadableStream.prototype, 'pipeThrough', 1, args);
+  methodThrows(ReadableStream.prototype, 'pipeThrough', { pipeTo: 'test' }, args);
+
+}, 'ReadableStream.prototype.pipeThrough should throw when "this" has no pipeTo method');
+
+test(() => {
+  const error = new Error('potato');
+
+  const throwingPipeTo = {
+    get pipeTo() {
+      throw error;
+    }
+  };
+  assert_throws(error,
+    () => ReadableStream.prototype.pipeThrough.call(throwingPipeTo, { readable: { }, writable: { } }, {}),
+    'pipeThrough should rethrow the error thrown by pipeTo');
+
+  const thisValue = {
+    pipeTo() {
+      assert_unreached('pipeTo should not be called');
+    }
+  };
+
+  const throwingWritable = {
+    readable: {},
+    get writable() {
+      throw error;
+    }
+  };
+  assert_throws(error,
+    () => ReadableStream.prototype.pipeThrough.call(thisValue, throwingWritable, {}),
+    'pipeThrough should rethrow the error thrown by the writable getter');
+
+  const throwingReadable = {
+    get readable() {
+      throw error;
+    },
+    writable: {}
+  };
+  assert_throws(error,
+    () => ReadableStream.prototype.pipeThrough.call(thisValue, throwingReadable, {}),
+    'pipeThrough should rethrow the error thrown by the readable getter');
+
+}, 'ReadableStream.prototype.pipeThrough should rethrow errors from accessing pipeTo, readable, or writable');
+
+test(() => {
+
+  let count = 0;
+  const thisValue = {
+    pipeTo() {
+      ++count;
+    }
+  };
+
+  ReadableStream.prototype.pipeThrough.call(thisValue, { readable: {}, writable: {} });
+  ReadableStream.prototype.pipeThrough.call(thisValue, { readable: {} }, {});
+  ReadableStream.prototype.pipeThrough.call(thisValue, { writable: {} }, {});
+
+  assert_equals(count, 3, 'pipeTo was called 3 times');
+
+}, 'ReadableStream.prototype.pipeThrough should work with missing readable, writable, or options');
+
+done();