test: support tests that include color information (#20220)

packages/cli/src/test-utils/mockDebugLogger.ts

@@ -0,0 +1,76 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi } from 'vitest';
+import stripAnsi from 'strip-ansi';
+import { format } from 'node:util';
+
+export function createMockDebugLogger(options: { stripAnsi?: boolean } = {}) {
+  const emitConsoleLog = vi.fn();
+  const debugLogger = {
+    log: vi.fn((message: unknown, ...args: unknown[]) => {
+      let formatted =
+        typeof message === 'string' ? format(message, ...args) : message;
+      if (options.stripAnsi && typeof formatted === 'string') {
+        formatted = stripAnsi(formatted);
+      }
+      emitConsoleLog('log', formatted);
+    }),
+    error: vi.fn((message: unknown, ...args: unknown[]) => {
+      let formatted =
+        typeof message === 'string' ? format(message, ...args) : message;
+      if (options.stripAnsi && typeof formatted === 'string') {
+        formatted = stripAnsi(formatted);
+      }
+      emitConsoleLog('error', formatted);
+    }),
+    warn: vi.fn((message: unknown, ...args: unknown[]) => {
+      let formatted =
+        typeof message === 'string' ? format(message, ...args) : message;
+      if (options.stripAnsi && typeof formatted === 'string') {
+        formatted = stripAnsi(formatted);
+      }
+      emitConsoleLog('warn', formatted);
+    }),
+    debug: vi.fn(),
+    info: vi.fn(),
+  };
+
+  return { emitConsoleLog, debugLogger };
+}
+
+/**
+ * A helper specifically designed for `vi.mock('@google/gemini-cli-core', ...)` to easily
+ * mock both `debugLogger` and `coreEvents.emitConsoleLog`.
+ *
+ * Example:
+ * ```typescript
+ * vi.mock('@google/gemini-cli-core', async (importOriginal) => {
+ *   const { mockCoreDebugLogger } = await import('../../test-utils/mockDebugLogger.js');
+ *   return mockCoreDebugLogger(
+ *     await importOriginal<typeof import('@google/gemini-cli-core')>(),
+ *     { stripAnsi: true }
+ *   );
+ * });
+ * ```
+ */
+export function mockCoreDebugLogger<T extends Record<string, unknown>>(
+  actual: T,
+  options?: { stripAnsi?: boolean },
+): T {
+  const { emitConsoleLog, debugLogger } = createMockDebugLogger(options);
+  return {
+    ...actual,
+    coreEvents: {
+      ...(typeof actual['coreEvents'] === 'object' &&
+      actual['coreEvents'] !== null
+        ? actual['coreEvents']
+        : {}),
+      emitConsoleLog,
+    },
+    debugLogger,
+  } as T;
+}