1 files changed, 25 insertions, 0 deletions
diff --git a/spec/frontend/behaviors/markdown/render_mermaid_spec.js b/spec/frontend/behaviors/markdown/render_mermaid_spec.js
new file mode 100644
index 00000000000..51a345cab0e
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+++ b/spec/frontend/behaviors/markdown/render_mermaid_spec.js
@@ -0,0 +1,25 @@
+import { initMermaid } from '~/behaviors/markdown/render_mermaid';
+import * as ColorUtils from '~/lib/utils/color_utils';
+
+describe('Render mermaid diagrams for Gitlab Flavoured Markdown', () => {
+  it.each`
+    darkMode | expectedTheme
+    ${false} | ${'neutral'}
+    ${true}  | ${'dark'}
+  `('is $darkMode $expectedTheme', async ({ darkMode, expectedTheme }) => {
+    jest.spyOn(ColorUtils, 'darkModeEnabled').mockImplementation(() => darkMode);
+
+    const mermaid = {
+      initialize: jest.fn(),
+    };
+
+    await initMermaid(mermaid);
+
+    expect(mermaid.initialize).toHaveBeenCalledTimes(1);
+    expect(mermaid.initialize).toHaveBeenCalledWith(
+      expect.objectContaining({
+        theme: expectedTheme,
+      }),
+    );
+  });
+});