test(core): align test fixtures with WorkspaceContext signature and GEMINI.md rename

- ls, shell, write-file tests: pass allowExternalFileAccess=false to
  WorkspaceContext constructor (third arg added to signature)
- pathReader test: add options.allowExternalFileAccess param to
  createMockConfig + fileService passthrough fallback so security
  tests don't need a custom FileDiscoveryService
- prompts test + snapshot: rename AGENTS.md -> GEMINI.md to match
  snippets.legacy.ts source

Author: hotmanxp

packages/core/src/core/__snapshots__/prompts.test.ts.snap

@@ -338,7 +338,7 @@ describe('Core System Prompt (prompts.ts)', () => {
     const memory = 'This is custom user memory.\nBe extra polite.';
     const prompt = getCoreSystemPrompt(mockConfig, memory);
 
-    expect(prompt).toContain('# Contextual Instructions (AGENTS.md)');
+    expect(prompt).toContain('# Contextual Instructions (GEMINI.md)');
     expect(prompt).toContain('<loaded_context>');
     expect(prompt).toContain(memory);
     expect(prompt).toContain('You are Gemini CLI, an interactive CLI agent'); // Ensure base prompt follows

packages/core/src/core/prompts.test.ts

@@ -46,7 +46,7 @@ describe('LSTool', () => {
     mockConfig = {
       getTargetDir: () => tempRootDir,
       getWorkspaceContext: () =>
-        new WorkspaceContext(tempRootDir, [tempSecondaryDir]),
+        new WorkspaceContext(tempRootDir, [tempSecondaryDir], false),
       getFileService: () => new FileDiscoveryService(tempRootDir),
       getFileFilteringOptions: () => ({
         respectGitIgnore: true,

packages/core/src/tools/ls.test.ts

@@ -127,7 +127,7 @@ describe('ShellTool', () => {
       getSummarizeToolOutputConfig: vi.fn().mockReturnValue(undefined),
       getWorkspaceContext: vi
         .fn()
-        .mockReturnValue(new WorkspaceContext(tempRootDir)),
+        .mockReturnValue(new WorkspaceContext(tempRootDir, [], false)),
       storage: {
         getProjectTempDir: vi.fn().mockReturnValue('/tmp/project'),
       },

packages/core/src/tools/shell.test.ts

@@ -83,7 +83,7 @@ const mockConfigInternal = {
   getBaseLlmClient: vi.fn(), // Initialize as a plain mock function
   getFileSystemService: () => fsService,
   getIdeMode: vi.fn(() => false),
-  getWorkspaceContext: () => new WorkspaceContext(rootDir, [plansDir]),
+  getWorkspaceContext: () => new WorkspaceContext(rootDir, [plansDir], false),
   getApiKey: () => 'test-key',
   getModel: () => 'test-model',
   getSandbox: () => false,
@@ -145,7 +145,7 @@ describe('WriteFileTool', () => {
       fs.mkdirSync(plansDir, { recursive: true });
     }
 
-    const workspaceContext = new WorkspaceContext(rootDir, [plansDir]);
+    const workspaceContext = new WorkspaceContext(rootDir, [plansDir], false);
     const mockStorage = {
       getProjectTempDir: vi.fn().mockReturnValue('/tmp/project'),
     };

packages/core/src/tools/write-file.test.ts

@@ -24,16 +24,31 @@ const createMockConfig = (
     respectGitIgnore?: boolean;
     respectGeminiIgnore?: boolean;
   } = {},
+  options: {
+    allowExternalFileAccess?: boolean;
+  } = {},
 ): Config => {
   const { respectGitIgnore = true, respectGeminiIgnore = true } = fileFiltering;
-  const workspace = new WorkspaceContext(cwd, otherDirs);
+  const { allowExternalFileAccess = false } = options;
+  const workspace = new WorkspaceContext(
+    cwd,
+    otherDirs,
+    allowExternalFileAccess,
+  );
   const fileSystemService = new StandardFileSystemService();
+  // Fallback passthrough so security tests can exercise pathReader without
+  // crafting a custom FileDiscoveryService for every case.
+  const fileService: FileDiscoveryService =
+    mockFileService ??
+    ({
+      filterFiles: (files: string[]) => files,
+    } as unknown as FileDiscoveryService);
   return {
     getWorkspaceContext: () => workspace,
     // TargetDir is used by processSingleFileContent to generate relative paths in errors/output
     getTargetDir: () => cwd,
     getFileSystemService: () => fileSystemService,
-    getFileService: () => mockFileService,
+    getFileService: () => fileService,
     getFileFilteringRespectGitIgnore: () => respectGitIgnore,
     getFileFilteringRespectGeminiIgnore: () => respectGeminiIgnore,
   } as unknown as Config;