1 files changed, 86 insertions, 0 deletions
diff --git a/packages/core/src/telemetry/metrics.test.ts b/packages/core/src/telemetry/metrics.test.ts
new file mode 100644
index 00000000..b7864131
--- /dev/null
+++ b/packages/core/src/telemetry/metrics.test.ts
@@ -0,0 +1,86 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, type Mock } from 'vitest';
+import { Counter, Meter, metrics } from '@opentelemetry/api';
+import { initializeMetrics, recordTokenUsageMetrics } from './metrics.js';
+
+const mockCounter = {
+  add: vi.fn(),
+} as unknown as Counter;
+
+const mockMeter = {
+  createCounter: vi.fn().mockReturnValue(mockCounter),
+  createHistogram: vi.fn().mockReturnValue({ record: vi.fn() }),
+} as unknown as Meter;
+
+vi.mock('@opentelemetry/api', () => ({
+  metrics: {
+    getMeter: vi.fn(),
+  },
+  ValueType: {
+    INT: 1,
+  },
+}));
+
+describe('Telemetry Metrics', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    (metrics.getMeter as Mock).mockReturnValue(mockMeter);
+  });
+
+  describe('recordTokenUsageMetrics', () => {
+    it('should not record metrics if not initialized', () => {
+      recordTokenUsageMetrics('gemini-pro', 100, 'input');
+      expect(mockCounter.add).not.toHaveBeenCalled();
+    });
+
+    it('should record token usage with the correct attributes', () => {
+      initializeMetrics();
+      recordTokenUsageMetrics('gemini-pro', 100, 'input');
+      expect(mockCounter.add).toHaveBeenCalledWith(100, {
+        model: 'gemini-pro',
+        type: 'input',
+      });
+    });
+
+    it('should record token usage for different types', () => {
+      initializeMetrics();
+      recordTokenUsageMetrics('gemini-pro', 50, 'output');
+      expect(mockCounter.add).toHaveBeenCalledWith(50, {
+        model: 'gemini-pro',
+        type: 'output',
+      });
+
+      recordTokenUsageMetrics('gemini-pro', 25, 'thought');
+      expect(mockCounter.add).toHaveBeenCalledWith(25, {
+        model: 'gemini-pro',
+        type: 'thought',
+      });
+
+      recordTokenUsageMetrics('gemini-pro', 75, 'cache');
+      expect(mockCounter.add).toHaveBeenCalledWith(75, {
+        model: 'gemini-pro',
+        type: 'cache',
+      });
+
+      recordTokenUsageMetrics('gemini-pro', 125, 'tool');
+      expect(mockCounter.add).toHaveBeenCalledWith(125, {
+        model: 'gemini-pro',
+        type: 'tool',
+      });
+    });
+
+    it('should handle different models', () => {
+      initializeMetrics();
+      recordTokenUsageMetrics('gemini-ultra', 200, 'input');
+      expect(mockCounter.add).toHaveBeenCalledWith(200, {
+        model: 'gemini-ultra',
+        type: 'input',
+      });
+    });
+  });
+});