Code-MCP

import { describe, it, expect, beforeEach, afterEach, vi } from "vitest"; // ============================================ // Code to Test // ============================================ class Calculator { add(a: number, b: number) { return a + b; } divide(a: number, b: number) { if (b === 0) throw new Error("Cannot divide by zero"); return a / b; } async fetchData(api: () => Promise<any>) { try { return await api(); } catch (e) { return null; } } } // ============================================ // Unit Tests // ============================================ describe("Calculator", () => { let calculator: Calculator; beforeEach(() => { calculator = new Calculator(); }); describe("Math Operations", () => { it("should add two numbers correctly", () => { const result = calculator.add(2, 3); expect(result).toBe(5); }); it("should handle negative numbers", () => { expect(calculator.add(-1, -1)).toBe(-2); expect(calculator.add(-1, 1)).toBe(0); }); it("should divide correctly", () => { expect(calculator.divide(6, 2)).toBe(3); }); it("should throw error when dividing by zero", () => { expect(() => calculator.divide(1, 0)).toThrow("Cannot divide by zero"); }); }); // ============================================ // Mocking Example // ============================================ describe("Async Operations", () => { it("should return data from api", async () => { const mockApi = vi.fn().mockResolvedValue({ id: 1 }); const result = await calculator.fetchData(mockApi); expect(result).toEqual({ id: 1 }); expect(mockApi).toHaveBeenCalledTimes(1); }); it("should return null on failure", async () => { const mockApi = vi.fn().mockRejectedValue(new Error("Fail")); const result = await calculator.fetchData(mockApi); expect(result).toBeNull(); }); }); }); // ============================================ // Snapshot Testing Example // ============================================ describe("Snapshots", () => { it("should match user config snapshot", () => { const config = { theme: "dark", version: "1.0.0", features: ["a", "b"], timestamp: new Date("2024-01-01").toISOString(), }; expect(config).toMatchSnapshot(); // Inline snapshot for simpler values expect(config.theme).toMatchInlineSnapshot('"dark"'); }); });