1 files changed, 53 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/readable-byte-streams/construct-byob-request.any.js b/testing/web-platform/tests/streams/readable-byte-streams/construct-byob-request.any.js
new file mode 100644
index 0000000000..8d460a1c81
--- /dev/null
+++ b/testing/web-platform/tests/streams/readable-byte-streams/construct-byob-request.any.js
@@ -0,0 +1,53 @@
+// META: global=window,worker
+// META: script=../resources/rs-utils.js
+'use strict';
+
+// Prior to whatwg/stream#870 it was possible to construct a ReadableStreamBYOBRequest directly. This made it possible
+// to construct requests that were out-of-sync with the state of the ReadableStream. They could then be used to call
+// internal operations, resulting in asserts or bad behaviour. This file contains regression tests for the change.
+
+function getRealByteStreamController() {
+  let controller;
+  new ReadableStream({
+    start(c) {
+      controller = c;
+    },
+    type: 'bytes'
+  });
+  return controller;
+}
+
+// Create an object pretending to have prototype |prototype|, of type |type|. |type| is one of "undefined", "null",
+// "fake", or "real". "real" will call the realObjectCreator function to get a real instance of the object.
+function createDummyObject(prototype, type, realObjectCreator) {
+  switch (type) {
+    case 'undefined':
+      return undefined;
+
+    case 'null':
+      return null;
+
+    case 'fake':
+      return Object.create(prototype);
+
+    case 'real':
+      return realObjectCreator();
+  }
+
+  throw new Error('not reached');
+}
+
+const dummyTypes = ['undefined', 'null', 'fake', 'real'];
+
+for (const controllerType of dummyTypes) {
+  const controller = createDummyObject(ReadableByteStreamController.prototype, controllerType,
+                                        getRealByteStreamController);
+  for (const viewType of dummyTypes) {
+    const view = createDummyObject(Uint8Array.prototype, viewType, () => new Uint8Array(16));
+    test(() => {
+      assert_throws_js(TypeError, () => new ReadableStreamBYOBRequest(controller, view),
+                        'constructor should throw');
+    }, `ReadableStreamBYOBRequest constructor should throw when passed a ${controllerType} ` +
+        `ReadableByteStreamController and a ${viewType} view`);
+  }
+}