Improve code coverage for cli package (#13724)

packages/cli/src/utils/checks.test.ts

@@ -0,0 +1,32 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { checkExhaustive, assumeExhaustive } from './checks.js';
+
+describe('checks', () => {
+  describe('checkExhaustive', () => {
+    it('should throw an error with default message', () => {
+      expect(() => {
+        checkExhaustive('unexpected' as never);
+      }).toThrow('unexpected value unexpected!');
+    });
+
+    it('should throw an error with custom message', () => {
+      expect(() => {
+        checkExhaustive('unexpected' as never, 'custom message');
+      }).toThrow('custom message');
+    });
+  });
+
+  describe('assumeExhaustive', () => {
+    it('should do nothing', () => {
+      expect(() => {
+        assumeExhaustive('unexpected' as never);
+      }).not.toThrow();
+    });
+  });
+});