refactor(test): improve test mocks and fs utility

- Ensure `safeReadFile` handles empty content gracefully to prevent potential errors.
- Update Jest mocks for `fs` utility functions in tests to correctly spread original exports, improving test reliability.
- Add comprehensive `globalState` mocking in `migrateSettings` tests for better test coverage.

Author: devxpain

src/__tests__/migrateSettings.test.ts

@@ -48,6 +48,18 @@ describe("Settings Migration", () => {
 		// Mock extension context
 		mockContext = {
 			globalStorageUri: { fsPath: mockStoragePath },
+			globalState: {
+				get: jest.fn((key: string) => {
+					if (key === "clineCustomModes") {
+						return "some old custom modes content"
+					}
+					if (key === "customInstructions") {
+						return undefined
+					}
+					return undefined
+				}),
+				update: jest.fn().mockResolvedValue(undefined),
+			},
 		} as unknown as vscode.ExtensionContext
 
 		// Set global outputChannel for all tests

src/core/prompts/__tests__/custom-system-prompt.test.ts

@@ -16,6 +16,7 @@ const mockedFs = fs as jest.Mocked<typeof fs>
 
 // Mock the fileExistsAtPath function
 jest.mock("../../../utils/fs", () => ({
+	...(jest.requireActual("../../../utils/fs") as object), // Spread all original exports
 	fileExistsAtPath: jest.fn().mockResolvedValue(true),
 	createDirectoriesForFile: jest.fn().mockResolvedValue([]),
 }))

src/core/task/__tests__/Task.test.ts

@@ -140,6 +140,7 @@ jest.mock("../../../utils/storage", () => ({
 }))
 
 jest.mock("../../../utils/fs", () => ({
+	...(jest.requireActual("../../../utils/fs") as object), // Spread all original exports
 	fileExistsAtPath: jest.fn().mockImplementation((filePath) => {
 		return filePath.includes("ui_messages.json") || filePath.includes("api_conversation_history.json")
 	}),

src/utils/fs.ts

@@ -52,7 +52,7 @@ export async function fileExistsAtPath(filePath: string): Promise<boolean> {
 export async function safeReadFile(filePath: string): Promise<string> {
 	try {
 		const content = await fs.readFile(filePath, "utf-8")
-		return content.trim()
+		return content ? content.trim() : ""
 	} catch (err) {
 		const errorCode = (err as NodeJS.ErrnoException).code
 		if (!errorCode || !["ENOENT", "EISDIR"].includes(errorCode)) {