1 files changed, 46 insertions, 0 deletions
diff --git a/spec/frontend/streaming/html_stream_spec.js b/spec/frontend/streaming/html_stream_spec.js
new file mode 100644
index 00000000000..115a9ddc803
--- /dev/null
+++ b/spec/frontend/streaming/html_stream_spec.js
@@ -0,0 +1,46 @@
+import { HtmlStream } from '~/streaming/html_stream';
+import { ChunkWriter } from '~/streaming/chunk_writer';
+
+jest.mock('~/streaming/chunk_writer');
+
+describe('HtmlStream', () => {
+  let write;
+  let close;
+  let streamingElement;
+
+  beforeEach(() => {
+    write = jest.fn();
+    close = jest.fn();
+    jest.spyOn(Document.prototype, 'write').mockImplementation(write);
+    jest.spyOn(Document.prototype, 'close').mockImplementation(close);
+    jest.spyOn(Document.prototype, 'querySelector').mockImplementation(() => {
+      streamingElement = document.createElement('div');
+      return streamingElement;
+    });
+  });
+
+  it('attaches to original document', () => {
+    // eslint-disable-next-line no-new
+    new HtmlStream(document.body);
+    expect(document.body.contains(streamingElement)).toBe(true);
+  });
+
+  it('can write to a document', () => {
+    const htmlStream = new HtmlStream(document.body);
+    htmlStream.write('foo');
+    htmlStream.close();
+    expect(write.mock.calls).toEqual([['<streaming-element>'], ['foo'], ['</streaming-element>']]);
+    expect(close).toHaveBeenCalledTimes(1);
+  });
+
+  it('returns chunked writer', () => {
+    const htmlStream = new HtmlStream(document.body).withChunkWriter();
+    expect(htmlStream).toBeInstanceOf(ChunkWriter);
+  });
+
+  it('closes on abort', () => {
+    const htmlStream = new HtmlStream(document.body);
+    htmlStream.abort();
+    expect(close).toHaveBeenCalled();
+  });
+});