test : added unit tests for error-handler logError function

test/error-handler.test.ts

@@ -0,0 +1,166 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { logError } from "../src/lib/error-handler";
+
+describe("logError", () => {
+  beforeEach(() => {
+    vi.spyOn(console, "error").mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("logs error message and context in development mode", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    const error = new Error("Test error message");
+    logError(error, {
+      endpoint: "/api/test",
+      operation: "testOperation",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("logs string error", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    logError("String error", {
+      endpoint: "/api/test",
+      operation: "testOperation",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("logs error with userId context", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    const error = new Error("User error");
+    logError(error, {
+      endpoint: "/api/user",
+      operation: "getUser",
+      userId: "user-123",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+    const logCalls = (console.error as any).mock.calls;
+    expect(logCalls.length).toBeGreaterThan(0);
+    const lastCall = logCalls[logCalls.length - 1];
+    const logObj = lastCall[lastCall.length - 1];
+    expect(logObj.endpoint).toBe("/api/user");
+    expect(logObj.userId).toBe("user-123");
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("logs error with additional context", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    const error = new Error("Context error");
+    logError(error, {
+      endpoint: "/api/data",
+      operation: "fetchData",
+      additionalContext: { repoId: "repo-456", cacheKey: "key-789" },
+    });
+
+    expect(console.error).toHaveBeenCalled();
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("handles null error gracefully", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    logError(null, {
+      endpoint: "/api/test",
+      operation: "testOperation",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("handles undefined error gracefully", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "development" },
+      writable: true,
+    });
+
+    logError(undefined, {
+      endpoint: "/api/test",
+      operation: "testOperation",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+
+  it("does not include stack traces in production", () => {
+    const originalEnv = process.env.NODE_ENV;
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: "production" },
+      writable: true,
+    });
+
+    const error = new Error("Production error");
+    logError(error, {
+      endpoint: "/api/test",
+      operation: "testOperation",
+    });
+
+    expect(console.error).toHaveBeenCalled();
+    const logCalls = (console.error as any).mock.calls;
+    expect(logCalls.length).toBeGreaterThan(0);
+
+    Object.defineProperty(process, "env", {
+      value: { ...process.env, NODE_ENV: originalEnv },
+      writable: true,
+    });
+  });
+});