Improve test coverage for cli/src/ui/components (#13598)

packages/cli/src/ui/components/ContextUsageDisplay.test.tsx

@@ -0,0 +1,61 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { render } from '../../test-utils/render.js';
+import { ContextUsageDisplay } from './ContextUsageDisplay.js';
+import { describe, it, expect, vi } from 'vitest';
+
+vi.mock('@google/gemini-cli-core', () => ({
+  tokenLimit: () => 10000,
+}));
+
+vi.mock('../../config/settings.js', () => ({
+  DEFAULT_MODEL_CONFIGS: {},
+  LoadedSettings: class {
+    constructor() {
+      // this.merged = {};
+    }
+  },
+}));
+
+describe('ContextUsageDisplay', () => {
+  it('renders correct percentage left', () => {
+    const { lastFrame } = render(
+      <ContextUsageDisplay
+        promptTokenCount={5000}
+        model="gemini-pro"
+        terminalWidth={120}
+      />,
+    );
+    const output = lastFrame();
+    expect(output).toContain('50% context left');
+  });
+
+  it('renders short label when terminal width is small', () => {
+    const { lastFrame } = render(
+      <ContextUsageDisplay
+        promptTokenCount={2000}
+        model="gemini-pro"
+        terminalWidth={80}
+      />,
+    );
+    const output = lastFrame();
+    expect(output).toContain('80%');
+    expect(output).not.toContain('context left');
+  });
+
+  it('renders 0% when full', () => {
+    const { lastFrame } = render(
+      <ContextUsageDisplay
+        promptTokenCount={10000}
+        model="gemini-pro"
+        terminalWidth={120}
+      />,
+    );
+    const output = lastFrame();
+    expect(output).toContain('0% context left');
+  });
+});