1 files changed, 16 insertions, 0 deletions
diff --git a/spec/frontend/content_editor/extensions/diagram_spec.js b/spec/frontend/content_editor/extensions/diagram_spec.js
new file mode 100644
index 00000000000..b8d9e0b5aeb
--- /dev/null
+++ b/spec/frontend/content_editor/extensions/diagram_spec.js
@@ -0,0 +1,16 @@
+import Diagram from '~/content_editor/extensions/diagram';
+import CodeBlockHighlight from '~/content_editor/extensions/code_block_highlight';
+
+describe('content_editor/extensions/diagram', () => {
+  it('inherits from code block highlight extension', () => {
+    expect(Diagram.parent).toBe(CodeBlockHighlight);
+  });
+
+  it('sets isDiagram attribute to true by default', () => {
+    expect(Diagram.config.addAttributes()).toEqual(
+      expect.objectContaining({
+        isDiagram: { default: true },
+      }),
+    );
+  });
+});