1 files changed, 369 insertions, 0 deletions
diff --git a/packages/server/src/utils/memoryDiscovery.test.ts b/packages/server/src/utils/memoryDiscovery.test.ts
new file mode 100644
index 00000000..d104df7a
--- /dev/null
+++ b/packages/server/src/utils/memoryDiscovery.test.ts
@@ -0,0 +1,369 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  vi,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  // afterEach, // Removed unused import
+  Mocked,
+} from 'vitest';
+import * as fsPromises from 'fs/promises';
+import * as fsSync from 'fs'; // For constants
+import { Stats, Dirent } from 'fs'; // Import types directly from 'fs'
+import * as os from 'os';
+import * as path from 'path';
+import { loadServerHierarchicalMemory } from './memoryDiscovery.js';
+import { GEMINI_CONFIG_DIR, GEMINI_MD_FILENAME } from '../tools/memoryTool.js';
+
+// Mock the entire fs/promises module
+vi.mock('fs/promises');
+// Mock the parts of fsSync we might use (like constants or existsSync if needed)
+vi.mock('fs', async (importOriginal) => {
+  const actual = await importOriginal<typeof fsSync>();
+  return {
+    ...actual, // Spread actual to get all exports, including Stats and Dirent if they are classes/constructors
+    constants: { ...actual.constants }, // Preserve constants
+    // Mock other fsSync functions if directly used by memoryDiscovery, e.g., existsSync
+    // existsSync: vi.fn(),
+  };
+});
+vi.mock('os');
+
+describe('loadServerHierarchicalMemory', () => {
+  const mockFs = fsPromises as Mocked<typeof fsPromises>;
+  const mockOs = os as Mocked<typeof os>;
+
+  const CWD = '/test/project/src';
+  const PROJECT_ROOT = '/test/project';
+  const USER_HOME = '/test/userhome';
+  const GLOBAL_GEMINI_DIR = path.join(USER_HOME, GEMINI_CONFIG_DIR);
+  const GLOBAL_GEMINI_FILE = path.join(GLOBAL_GEMINI_DIR, GEMINI_MD_FILENAME);
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+
+    mockOs.homedir.mockReturnValue(USER_HOME);
+    mockFs.stat.mockRejectedValue(new Error('File not found'));
+    mockFs.readdir.mockResolvedValue([]);
+    mockFs.readFile.mockRejectedValue(new Error('File not found'));
+    mockFs.access.mockRejectedValue(new Error('File not found'));
+  });
+
+  it('should return empty memory and count if no GEMINI.md files are found', async () => {
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+    expect(memoryContent).toBe('');
+    expect(fileCount).toBe(0);
+  });
+
+  it('should load only the global GEMINI.md if present and others are not', async () => {
+    mockFs.access.mockImplementation(async (p) => {
+      if (p === GLOBAL_GEMINI_FILE) {
+        return undefined;
+      }
+      throw new Error('File not found');
+    });
+    mockFs.readFile.mockImplementation(async (p) => {
+      if (p === GLOBAL_GEMINI_FILE) {
+        return 'Global memory content';
+      }
+      throw new Error('File not found');
+    });
+
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+
+    expect(memoryContent).toBe(
+      `--- Context from: ${path.relative(CWD, GLOBAL_GEMINI_FILE)} ---\nGlobal memory content\n--- End of Context from: ${path.relative(CWD, GLOBAL_GEMINI_FILE)} ---`,
+    );
+    expect(fileCount).toBe(1);
+    expect(mockFs.readFile).toHaveBeenCalledWith(GLOBAL_GEMINI_FILE, 'utf-8');
+  });
+
+  it('should load GEMINI.md files by upward traversal from CWD to project root', async () => {
+    const projectRootGeminiFile = path.join(PROJECT_ROOT, GEMINI_MD_FILENAME);
+    const srcGeminiFile = path.join(CWD, GEMINI_MD_FILENAME);
+
+    mockFs.stat.mockImplementation(async (p) => {
+      if (p === path.join(PROJECT_ROOT, '.git')) {
+        return { isDirectory: () => true } as Stats;
+      }
+      throw new Error('File not found');
+    });
+
+    mockFs.access.mockImplementation(async (p) => {
+      if (p === projectRootGeminiFile || p === srcGeminiFile) {
+        return undefined;
+      }
+      throw new Error('File not found');
+    });
+
+    mockFs.readFile.mockImplementation(async (p) => {
+      if (p === projectRootGeminiFile) {
+        return 'Project root memory';
+      }
+      if (p === srcGeminiFile) {
+        return 'Src directory memory';
+      }
+      throw new Error('File not found');
+    });
+
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+    const expectedContent =
+      `--- Context from: ${path.relative(CWD, projectRootGeminiFile)} ---\nProject root memory\n--- End of Context from: ${path.relative(CWD, projectRootGeminiFile)} ---\n\n` +
+      `--- Context from: ${GEMINI_MD_FILENAME} ---\nSrc directory memory\n--- End of Context from: ${GEMINI_MD_FILENAME} ---`;
+
+    expect(memoryContent).toBe(expectedContent);
+    expect(fileCount).toBe(2);
+    expect(mockFs.readFile).toHaveBeenCalledWith(
+      projectRootGeminiFile,
+      'utf-8',
+    );
+    expect(mockFs.readFile).toHaveBeenCalledWith(srcGeminiFile, 'utf-8');
+  });
+
+  it('should load GEMINI.md files by downward traversal from CWD', async () => {
+    const subDir = path.join(CWD, 'subdir');
+    const subDirGeminiFile = path.join(subDir, GEMINI_MD_FILENAME);
+    const cwdGeminiFile = path.join(CWD, GEMINI_MD_FILENAME);
+
+    mockFs.access.mockImplementation(async (p) => {
+      if (p === cwdGeminiFile || p === subDirGeminiFile) return undefined;
+      throw new Error('File not found');
+    });
+
+    mockFs.readFile.mockImplementation(async (p) => {
+      if (p === cwdGeminiFile) return 'CWD memory';
+      if (p === subDirGeminiFile) return 'Subdir memory';
+      throw new Error('File not found');
+    });
+
+    mockFs.readdir.mockImplementation(async (p) => {
+      if (p === CWD) {
+        return [
+          {
+            name: GEMINI_MD_FILENAME,
+            isFile: () => true,
+            isDirectory: () => false,
+          },
+          { name: 'subdir', isFile: () => false, isDirectory: () => true },
+        ] as Dirent[];
+      }
+      if (p === subDir) {
+        return [
+          {
+            name: GEMINI_MD_FILENAME,
+            isFile: () => true,
+            isDirectory: () => false,
+          },
+        ] as Dirent[];
+      }
+      return [];
+    });
+
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+    const expectedContent =
+      `--- Context from: ${GEMINI_MD_FILENAME} ---\nCWD memory\n--- End of Context from: ${GEMINI_MD_FILENAME} ---\n\n` +
+      `--- Context from: ${path.join('subdir', GEMINI_MD_FILENAME)} ---\nSubdir memory\n--- End of Context from: ${path.join('subdir', GEMINI_MD_FILENAME)} ---`;
+
+    expect(memoryContent).toBe(expectedContent);
+    expect(fileCount).toBe(2);
+  });
+
+  it('should load and correctly order global, upward, and downward GEMINI.md files', async () => {
+    const projectParentDir = path.dirname(PROJECT_ROOT);
+    const projectParentGeminiFile = path.join(
+      projectParentDir,
+      GEMINI_MD_FILENAME,
+    );
+    const projectRootGeminiFile = path.join(PROJECT_ROOT, GEMINI_MD_FILENAME);
+    const cwdGeminiFile = path.join(CWD, GEMINI_MD_FILENAME);
+    const subDir = path.join(CWD, 'sub');
+    const subDirGeminiFile = path.join(subDir, GEMINI_MD_FILENAME);
+
+    mockFs.stat.mockImplementation(async (p) => {
+      if (p === path.join(PROJECT_ROOT, '.git')) {
+        return { isDirectory: () => true } as Stats;
+      }
+      throw new Error('File not found');
+    });
+
+    mockFs.access.mockImplementation(async (p) => {
+      if (
+        p === GLOBAL_GEMINI_FILE ||
+        p === projectParentGeminiFile ||
+        p === projectRootGeminiFile ||
+        p === cwdGeminiFile ||
+        p === subDirGeminiFile
+      ) {
+        return undefined;
+      }
+      throw new Error('File not found');
+    });
+
+    mockFs.readFile.mockImplementation(async (p) => {
+      if (p === GLOBAL_GEMINI_FILE) return 'Global memory';
+      if (p === projectParentGeminiFile) return 'Project parent memory';
+      if (p === projectRootGeminiFile) return 'Project root memory';
+      if (p === cwdGeminiFile) return 'CWD memory';
+      if (p === subDirGeminiFile) return 'Subdir memory';
+      throw new Error('File not found');
+    });
+
+    mockFs.readdir.mockImplementation(async (p) => {
+      if (p === CWD) {
+        return [
+          { name: 'sub', isFile: () => false, isDirectory: () => true },
+        ] as Dirent[];
+      }
+      if (p === subDir) {
+        return [
+          {
+            name: GEMINI_MD_FILENAME,
+            isFile: () => true,
+            isDirectory: () => false,
+          },
+        ] as Dirent[];
+      }
+      return [];
+    });
+
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+
+    const relPathGlobal = path.relative(CWD, GLOBAL_GEMINI_FILE);
+    const relPathProjectParent = path.relative(CWD, projectParentGeminiFile);
+    const relPathProjectRoot = path.relative(CWD, projectRootGeminiFile);
+    const relPathCwd = GEMINI_MD_FILENAME;
+    const relPathSubDir = path.join('sub', GEMINI_MD_FILENAME);
+
+    const expectedContent = [
+      `--- Context from: ${relPathGlobal} ---\nGlobal memory\n--- End of Context from: ${relPathGlobal} ---`,
+      `--- Context from: ${relPathProjectParent} ---\nProject parent memory\n--- End of Context from: ${relPathProjectParent} ---`,
+      `--- Context from: ${relPathProjectRoot} ---\nProject root memory\n--- End of Context from: ${relPathProjectRoot} ---`,
+      `--- Context from: ${relPathCwd} ---\nCWD memory\n--- End of Context from: ${relPathCwd} ---`,
+      `--- Context from: ${relPathSubDir} ---\nSubdir memory\n--- End of Context from: ${relPathSubDir} ---`,
+    ].join('\n\n');
+
+    expect(memoryContent).toBe(expectedContent);
+    expect(fileCount).toBe(5);
+  });
+
+  it('should ignore specified directories during downward scan', async () => {
+    const ignoredDir = path.join(CWD, 'node_modules');
+    const ignoredDirGeminiFile = path.join(ignoredDir, GEMINI_MD_FILENAME);
+    const regularSubDir = path.join(CWD, 'my_code');
+    const regularSubDirGeminiFile = path.join(
+      regularSubDir,
+      GEMINI_MD_FILENAME,
+    );
+
+    mockFs.access.mockImplementation(async (p) => {
+      if (p === regularSubDirGeminiFile) return undefined;
+      if (p === ignoredDirGeminiFile)
+        throw new Error('Should not access ignored file');
+      throw new Error('File not found');
+    });
+
+    mockFs.readFile.mockImplementation(async (p) => {
+      if (p === regularSubDirGeminiFile) return 'My code memory';
+      throw new Error('File not found');
+    });
+
+    mockFs.readdir.mockImplementation(async (p) => {
+      if (p === CWD) {
+        return [
+          {
+            name: 'node_modules',
+            isFile: () => false,
+            isDirectory: () => true,
+          },
+          { name: 'my_code', isFile: () => false, isDirectory: () => true },
+        ] as Dirent[];
+      }
+      if (p === regularSubDir) {
+        return [
+          {
+            name: GEMINI_MD_FILENAME,
+            isFile: () => true,
+            isDirectory: () => false,
+          },
+        ] as Dirent[];
+      }
+      if (p === ignoredDir) {
+        return [
+          {
+            name: GEMINI_MD_FILENAME,
+            isFile: () => true,
+            isDirectory: () => false,
+          },
+        ] as Dirent[];
+      }
+      return [];
+    });
+
+    const { memoryContent, fileCount } = await loadServerHierarchicalMemory(
+      CWD,
+      false,
+    );
+
+    const expectedContent = `--- Context from: ${path.join('my_code', GEMINI_MD_FILENAME)} ---\nMy code memory\n--- End of Context from: ${path.join('my_code', GEMINI_MD_FILENAME)} ---`;
+
+    expect(memoryContent).toBe(expectedContent);
+    expect(fileCount).toBe(1);
+    expect(mockFs.readFile).not.toHaveBeenCalledWith(
+      ignoredDirGeminiFile,
+      'utf-8',
+    );
+  });
+
+  it('should respect MAX_DIRECTORIES_TO_SCAN_FOR_MEMORY during downward scan', async () => {
+    const consoleDebugSpy = vi
+      .spyOn(console, 'debug')
+      .mockImplementation(() => {});
+
+    const dirNames: Dirent[] = [];
+    for (let i = 0; i < 250; i++) {
+      dirNames.push({
+        name: `deep_dir_${i}`,
+        isFile: () => false,
+        isDirectory: () => true,
+      } as Dirent);
+    }
+
+    mockFs.readdir.mockImplementation(async (p) => {
+      if (p === CWD) return dirNames;
+      if (p.toString().startsWith(path.join(CWD, 'deep_dir_'))) return [];
+      return [];
+    });
+    mockFs.access.mockRejectedValue(new Error('not found'));
+
+    await loadServerHierarchicalMemory(CWD, true);
+
+    expect(consoleDebugSpy).toHaveBeenCalledWith(
+      expect.stringContaining('[DEBUG] [MemoryDiscovery]'),
+      expect.stringContaining(
+        'Max directory scan limit (200) reached. Stopping downward scan at:',
+      ),
+    );
+    consoleDebugSpy.mockRestore();
+  });
+});