feat(test-utils): add memory usage integration test harness (#24876)

memory-tests/globalSetup.ts

@@ -0,0 +1,71 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { mkdir, readdir, rm } from 'node:fs/promises';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { canUseRipgrep } from '../packages/core/src/tools/ripGrep.js';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const rootDir = join(__dirname, '..');
+const memoryTestsDir = join(rootDir, '.memory-tests');
+let runDir = '';
+
+export async function setup() {
+  runDir = join(memoryTestsDir, `${Date.now()}`);
+  await mkdir(runDir, { recursive: true });
+
+  // Set the home directory to the test run directory to avoid conflicts
+  // with the user's local config.
+  process.env['HOME'] = runDir;
+  if (process.platform === 'win32') {
+    process.env['USERPROFILE'] = runDir;
+  }
+  process.env['GEMINI_CONFIG_DIR'] = join(runDir, '.gemini');
+
+  // Download ripgrep to avoid race conditions
+  const available = await canUseRipgrep();
+  if (!available) {
+    throw new Error('Failed to download ripgrep binary');
+  }
+
+  // Clean up old test runs, keeping the latest few for debugging
+  try {
+    const testRuns = await readdir(memoryTestsDir);
+    if (testRuns.length > 3) {
+      const oldRuns = testRuns.sort().slice(0, testRuns.length - 3);
+      await Promise.all(
+        oldRuns.map((oldRun) =>
+          rm(join(memoryTestsDir, oldRun), {
+            recursive: true,
+            force: true,
+          }),
+        ),
+      );
+    }
+  } catch (e) {
+    console.error('Error cleaning up old memory test runs:', e);
+  }
+
+  process.env['INTEGRATION_TEST_FILE_DIR'] = runDir;
+  process.env['GEMINI_CLI_INTEGRATION_TEST'] = 'true';
+  process.env['GEMINI_FORCE_FILE_STORAGE'] = 'true';
+  process.env['TELEMETRY_LOG_FILE'] = join(runDir, 'telemetry.log');
+  process.env['VERBOSE'] = process.env['VERBOSE'] ?? 'false';
+
+  console.log(`\nMemory test output directory: ${runDir}`);
+}
+
+export async function teardown() {
+  // Cleanup unless KEEP_OUTPUT is set
+  if (process.env['KEEP_OUTPUT'] !== 'true' && runDir) {
+    try {
+      await rm(runDir, { recursive: true, force: true });
+    } catch (e) {
+      console.warn('Failed to clean up memory test directory:', e);
+    }
+  }
+}