[Part 4/6] feat(telemetry): add memory monitor with activity-aware recording and tests (#8122)

Co-authored-by: Jacob Richman <jacob314@gmail.com>

packages/core/src/utils/formatters.test.ts

@@ -0,0 +1,31 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+
+import { bytesToMB, formatMemoryUsage } from './formatters.js';
+
+describe('bytesToMB', () => {
+  it('converts bytes to megabytes', () => {
+    expect(bytesToMB(0)).toBe(0);
+    expect(bytesToMB(512 * 1024)).toBeCloseTo(0.5, 5);
+    expect(bytesToMB(5 * 1024 * 1024)).toBe(5);
+  });
+});
+
+describe('formatMemoryUsage', () => {
+  it('formats values below one megabyte in KB', () => {
+    expect(formatMemoryUsage(512 * 1024)).toBe('512.0 KB');
+  });
+
+  it('formats values below one gigabyte in MB', () => {
+    expect(formatMemoryUsage(5 * 1024 * 1024)).toBe('5.0 MB');
+  });
+
+  it('formats values of one gigabyte or larger in GB', () => {
+    expect(formatMemoryUsage(2 * 1024 * 1024 * 1024)).toBe('2.00 GB');
+  });
+});

packages/core/src/utils/formatters.ts

@@ -4,13 +4,15 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+export const bytesToMB = (bytes: number): number => bytes / (1024 * 1024);
+
 export const formatMemoryUsage = (bytes: number): string => {
   const gb = bytes / (1024 * 1024 * 1024);
   if (bytes < 1024 * 1024) {
     return `${(bytes / 1024).toFixed(1)} KB`;
   }
   if (bytes < 1024 * 1024 * 1024) {
-    return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
+    return `${bytesToMB(bytes).toFixed(1)} MB`;
   }
   return `${gb.toFixed(2)} GB`;
 };