MCP Screenshot Server

import { WSLCaptureEngine } from "./wsl-capture-engine"; import { exec } from "child_process"; import { CaptureFailedError, WindowNotFoundError } from "../errors"; // Mock child_process jest.mock("child_process", () => ({ exec: jest.fn(), })); describe("WSLCaptureEngine", () => { let engine: WSLCaptureEngine; let mockExec: jest.Mock; beforeEach(() => { engine = new WSLCaptureEngine(); mockExec = exec as unknown as jest.Mock; jest.clearAllMocks(); }); // Helper to mock exec success const mockExecSuccess = (stdout: string, stderr = "") => { mockExec.mockImplementation((cmd, options, callback) => { callback(null, { stdout, stderr }); }); }; // Helper to mock exec failure const mockExecError = (error: Error) => { mockExec.mockImplementation((cmd, options, callback) => { callback(error, { stdout: "", stderr: error.message }); }); }; describe("captureScreen", () => { it("should capture full screen successfully", async () => { const mockBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="; mockExecSuccess(mockBase64); const buffer = await engine.captureScreen(); expect(buffer).toBeInstanceOf(Buffer); expect(buffer.toString("base64")).toBe(mockBase64); expect(mockExec).toHaveBeenCalledWith( expect.stringContaining("powershell.exe"), expect.any(Object), expect.any(Function) ); }); it("should capture specific display successfully", async () => { const mockBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="; mockExecSuccess(mockBase64); const buffer = await engine.captureScreen("Display1"); expect(buffer).toBeInstanceOf(Buffer); expect(mockExec).toHaveBeenCalledWith( expect.stringContaining("Display1"), expect.any(Object), expect.any(Function) ); }); it("should throw CaptureFailedError on failure", async () => { mockExecError(new Error("PowerShell failed")); await expect(engine.captureScreen()).rejects.toThrow(CaptureFailedError); }); it("should throw error on empty output", async () => { mockExecSuccess(""); await expect(engine.captureScreen()).rejects.toThrow(CaptureFailedError); }); }); describe("captureWindow", () => { it("should capture window successfully", async () => { const mockBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="; mockExecSuccess(mockBase64); const buffer = await engine.captureWindow("12345", false); expect(buffer).toBeInstanceOf(Buffer); expect(mockExec).toHaveBeenCalledWith( expect.stringContaining("12345"), expect.any(Object), expect.any(Function) ); }); it("should throw WindowNotFoundError for minimized window", async () => { mockExecError(new Error("Window is minimized")); await expect(engine.captureWindow("12345", false)).rejects.toThrow( WindowNotFoundError ); }); it("should throw CaptureFailedError for other errors", async () => { mockExecError(new Error("Generic error")); await expect(engine.captureWindow("12345", false)).rejects.toThrow( CaptureFailedError ); }); }); describe("captureRegion", () => { it("should capture region successfully", async () => { const mockBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="; mockExecSuccess(mockBase64); // Mock getDisplays for region validation jest.spyOn(engine, "getDisplays").mockResolvedValue([ { id: "default", name: "Default", resolution: { width: 1920, height: 1080 }, position: { x: 0, y: 0 }, isPrimary: true, }, ]); const buffer = await engine.captureRegion(0, 0, 100, 100); expect(buffer).toBeInstanceOf(Buffer); expect(mockExec).toHaveBeenCalledWith( expect.stringContaining("CopyFromScreen"), expect.any(Object), expect.any(Function) ); }); }); describe("getDisplays", () => { it("should parse display info correctly", async () => { const mockOutput = JSON.stringify([ { id: "Display1", name: "Display1", width: 1920, height: 1080, x: 0, y: 0, primary: true, }, ]); mockExecSuccess(mockOutput); const displays = await engine.getDisplays(); expect(displays).toHaveLength(1); expect(displays[0]).toEqual({ id: "Display1", name: "Display1", resolution: { width: 1920, height: 1080 }, position: { x: 0, y: 0 }, isPrimary: true, }); }); it("should handle single display object (not array)", async () => { const mockOutput = JSON.stringify({ id: "Display1", name: "Display1", width: 1920, height: 1080, x: 0, y: 0, primary: true, }); mockExecSuccess(mockOutput); const displays = await engine.getDisplays(); expect(displays).toHaveLength(1); }); it("should return default display on error", async () => { mockExecError(new Error("Failed")); const displays = await engine.getDisplays(); expect(displays).toHaveLength(1); expect(displays[0].id).toBe("default"); }); }); describe("getWindows", () => { it("should parse window info correctly", async () => { const mockOutput = JSON.stringify([ { id: 12345, title: "Test Window", processId: 100, x: 10, y: 10, width: 800, height: 600, isMinimized: false, }, ]); mockExecSuccess(mockOutput); const windows = await engine.getWindows(); expect(windows).toHaveLength(1); expect(windows[0]).toEqual({ id: "12345", title: "Test Window", pid: 100, processName: undefined, bounds: { x: 10, y: 10, width: 800, height: 600 }, isMinimized: false, }); }); it("should return empty array on error", async () => { mockExecError(new Error("Failed")); const windows = await engine.getWindows(); expect(windows).toEqual([]); }); }); });