1 files changed, 37 insertions, 0 deletions
diff --git a/testing/web-platform/tests/encoding/streams/invalid-realm.window.js b/testing/web-platform/tests/encoding/streams/invalid-realm.window.js
new file mode 100644
index 0000000000..beaec42641
--- /dev/null
+++ b/testing/web-platform/tests/encoding/streams/invalid-realm.window.js
@@ -0,0 +1,37 @@
+// Text*Stream should still work even if the realm is detached.
+
+// Adds an iframe to the document and returns it.
+function addIframe() {
+  const iframe = document.createElement('iframe');
+  document.body.appendChild(iframe);
+  return iframe;
+}
+
+promise_test(async t => {
+  const iframe = addIframe();
+  const stream = new iframe.contentWindow.TextDecoderStream();
+  const readPromise = stream.readable.getReader().read();
+  const writer = stream.writable.getWriter();
+  await writer.ready;
+  iframe.remove();
+  return Promise.all([writer.write(new Uint8Array([65])),readPromise]);
+}, 'TextDecoderStream: write in detached realm should succeed');
+
+promise_test(async t => {
+  const iframe = addIframe();
+  const stream = new iframe.contentWindow.TextEncoderStream();
+  const readPromise = stream.readable.getReader().read();
+  const writer = stream.writable.getWriter();
+  await writer.ready;
+  iframe.remove();
+  return Promise.all([writer.write('A'), readPromise]);
+}, 'TextEncoderStream: write in detached realm should succeed');
+
+for (const type of ['TextEncoderStream', 'TextDecoderStream']) {
+  promise_test(async t => {
+    const iframe = addIframe();
+    const stream = new iframe.contentWindow[type]();
+    iframe.remove();
+    return stream.writable.close();
+  }, `${type}: close in detached realm should succeed`);
+}