diff --git a/packages/core/src/telemetry/clearcut-logger/event-metadata-key.test.ts b/packages/core/src/telemetry/clearcut-logger/event-metadata-key.test.ts
new file mode 100644
index 00000000000..ec94663e871
--- /dev/null
+++ b/packages/core/src/telemetry/clearcut-logger/event-metadata-key.test.ts
@@ -0,0 +1,38 @@
+import { describe, it, expect } from 'vitest';
+import {
+  EventMetadataKey,
+  getEventMetadataKey,
+} from './event-metadata-key.js';
+
+describe('getEventMetadataKey', () => {
+  it('should return the correct enum value for a valid key name', () => {
+    expect(getEventMetadataKey('GEMINI_CLI_START_SESSION_MODEL')).toBe(
+      EventMetadataKey.GEMINI_CLI_START_SESSION_MODEL,
+    );
+    expect(getEventMetadataKey('GEMINI_CLI_USER_PROMPT_LENGTH')).toBe(
+      EventMetadataKey.GEMINI_CLI_USER_PROMPT_LENGTH,
+    );
+    expect(getEventMetadataKey('GEMINI_CLI_END_SESSION_ID')).toBe(
+      EventMetadataKey.GEMINI_CLI_END_SESSION_ID,
+    );
+  });
+
+  it('should return undefined for an invalid key name', () => {
+    expect(getEventMetadataKey('INVALID_KEY_NAME')).toBeUndefined();
+    expect(getEventMetadataKey('')).toBeUndefined();
+    expect(getEventMetadataKey(' ')).toBeUndefined();
+  });
+
+  it('should return undefined for a number passed as a string', () => {
+    // EventMetadataKey[1] is 'GEMINI_CLI_START_SESSION_MODEL' in standard TS enums,
+    // but getEventMetadataKey should return undefined because typeof 'GEMINI_CLI_START_SESSION_MODEL' is string, not number.
+    expect(getEventMetadataKey('1')).toBeUndefined();
+    expect(getEventMetadataKey('0')).toBeUndefined();
+  });
+
+  it('should return undefined for built-in object properties', () => {
+    expect(getEventMetadataKey('toString')).toBeUndefined();
+    expect(getEventMetadataKey('valueOf')).toBeUndefined();
+    expect(getEventMetadataKey('__proto__')).toBeUndefined();
+  });
+});
diff --git a/packages/core/src/utils/errors.test.ts b/packages/core/src/utils/errors.test.ts
index ec42a3f954f..67362d48cc6 100644
--- a/packages/core/src/utils/errors.test.ts
+++ b/packages/core/src/utils/errors.test.ts
@@ -4,7 +4,7 @@ import {
   BadRequestError,
   UnauthorizedError,
   ForbiddenError,
-} from './errors';
+} from './errors.js';
 
 describe('toFriendlyError', () => {
   it('should return the original error if it is not an object', () => {