feat: add /features command and lifecycle visibility

packages/cli/src/ui/commands/featuresCommand.test.ts

@@ -0,0 +1,64 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, type vi } from 'vitest';
+import { featuresCommand } from './featuresCommand.js';
+import { createMockCommandContext } from '../../test-utils/mockCommandContext.js';
+import { MessageType, type HistoryItemFeaturesList } from '../types.js';
+import { FeatureStage } from '@google/gemini-cli-core';
+
+describe('featuresCommand', () => {
+  it('should display an error if the feature gate is unavailable', async () => {
+    const mockContext = createMockCommandContext({
+      services: {
+        config: {
+          getFeatureGate: () => undefined,
+        },
+      },
+    });
+
+    if (!featuresCommand.action) throw new Error('Action not defined');
+    await featuresCommand.action(mockContext, '');
+
+    expect(mockContext.ui.addItem).toHaveBeenCalledWith({
+      type: MessageType.ERROR,
+      text: 'Could not retrieve feature gate.',
+    });
+  });
+
+  it('should list alpha, beta, and deprecated features', async () => {
+    const mockFeatures = [
+      { key: 'alphaFeat', enabled: false, stage: FeatureStage.Alpha },
+      { key: 'betaFeat', enabled: true, stage: FeatureStage.Beta },
+      { key: 'deprecatedFeat', enabled: false, stage: FeatureStage.Deprecated },
+      { key: 'gaFeat', enabled: true, stage: FeatureStage.GA },
+    ];
+
+    const mockContext = createMockCommandContext({
+      services: {
+        config: {
+          getFeatureGate: () => ({
+            getFeatureInfo: () => mockFeatures,
+          }),
+        },
+      },
+    });
+
+    if (!featuresCommand.action) throw new Error('Action not defined');
+    await featuresCommand.action(mockContext, '');
+
+    const [message] = (mockContext.ui.addItem as ReturnType<typeof vi.fn>).mock
+      .calls[0];
+    const featuresList = message as HistoryItemFeaturesList;
+    expect(featuresList.type).toBe(MessageType.FEATURES_LIST);
+    expect(featuresList.features).toHaveLength(3);
+    expect(featuresList.features.map((f) => f.key)).toEqual([
+      'alphaFeat',
+      'betaFeat',
+      'deprecatedFeat',
+    ]);
+  });
+});