chore: add Jest test setup

Author: aboderinsamuel

__tests__/lib/auth.test.ts

@@ -0,0 +1,150 @@
+/**
+ * Unit tests for lib/auth.ts
+ * Tests input validation and error handling without hitting Supabase.
+ */
+
+// Mock the Supabase client before importing auth functions
+jest.mock("@/lib/supabase", () => ({
+  supabase: {
+    auth: {
+      signUp: jest.fn(),
+      signInWithPassword: jest.fn(),
+      getUser: jest.fn(),
+      getSession: jest.fn(),
+      signOut: jest.fn(),
+      onAuthStateChange: jest.fn(() => ({
+        data: { subscription: { unsubscribe: jest.fn() } },
+      })),
+    },
+    from: jest.fn(() => ({
+      select: jest.fn().mockReturnThis(),
+      eq: jest.fn().mockReturnThis(),
+      single: jest.fn().mockResolvedValue({ data: null, error: { message: "not found" } }),
+    })),
+  },
+}));
+
+import { registerUser, authenticateUser } from "@/lib/auth";
+import { supabase } from "@/lib/supabase";
+
+const mockAuth = supabase.auth as jest.Mocked<typeof supabase.auth>;
+
+// ─── registerUser ────────────────────────────────────────────────────────────
+
+describe("registerUser – input validation", () => {
+  it("rejects empty email and password", async () => {
+    const result = await registerUser("", "");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+
+  it("rejects missing email", async () => {
+    const result = await registerUser("", "validpassword");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+
+  it("rejects missing password", async () => {
+    const result = await registerUser("user@example.com", "");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+
+  it("rejects password shorter than 6 characters", async () => {
+    const result = await registerUser("user@example.com", "abc");
+    expect(result).toEqual({ ok: false, error: "Password must be at least 6 characters" });
+  });
+
+  it("accepts password of exactly 6 characters", async () => {
+    (mockAuth.signUp as jest.Mock).mockResolvedValueOnce({
+      data: { user: { id: "123", identities: [{}] }, session: { access_token: "tok" } },
+      error: null,
+    });
+    const result = await registerUser("user@example.com", "abc123");
+    expect(result.ok).toBe(true);
+  });
+});
+
+describe("registerUser – Supabase error handling", () => {
+  it("returns error message from Supabase on failure", async () => {
+    (mockAuth.signUp as jest.Mock).mockResolvedValueOnce({
+      data: { user: null, session: null },
+      error: { message: "User already registered" },
+    });
+    const result = await registerUser("user@example.com", "password123");
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error).toContain("already registered");
+    }
+  });
+
+  it("flags needsEmailConfirmation when no session returned", async () => {
+    (mockAuth.signUp as jest.Mock).mockResolvedValueOnce({
+      data: { user: { id: "abc", identities: [{}] }, session: null },
+      error: null,
+    });
+    const result = await registerUser("user@example.com", "password123");
+    expect(result).toMatchObject({ ok: true, needsEmailConfirmation: true });
+  });
+
+  it("returns network error message on thrown exception", async () => {
+    (mockAuth.signUp as jest.Mock).mockRejectedValueOnce(new Error("fetch failed"));
+    const result = await registerUser("user@example.com", "password123");
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error).toMatch(/fetch failed/i);
+  });
+});
+
+// ─── authenticateUser ────────────────────────────────────────────────────────
+
+describe("authenticateUser – input validation", () => {
+  it("rejects empty email and password", async () => {
+    const result = await authenticateUser("", "");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+
+  it("rejects missing email", async () => {
+    const result = await authenticateUser("", "password123");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+
+  it("rejects missing password", async () => {
+    const result = await authenticateUser("user@example.com", "");
+    expect(result).toEqual({ ok: false, error: "Email and password are required" });
+  });
+});
+
+describe("authenticateUser – Supabase error handling", () => {
+  it("maps invalid credentials to a friendly message", async () => {
+    (mockAuth.signInWithPassword as jest.Mock).mockResolvedValueOnce({
+      data: { user: null, session: null },
+      error: { message: "Invalid login credentials" },
+    });
+    const result = await authenticateUser("user@example.com", "wrongpassword");
+    expect(result).toEqual({ ok: false, error: "Invalid email or password" });
+  });
+
+  it("maps unconfirmed email to a friendly message", async () => {
+    (mockAuth.signInWithPassword as jest.Mock).mockResolvedValueOnce({
+      data: { user: null, session: null },
+      error: { message: "Email not confirmed" },
+    });
+    const result = await authenticateUser("user@example.com", "password123");
+    expect(result).toEqual({ ok: false, error: "Please verify your email first" });
+  });
+
+  it("returns ok:true on successful login", async () => {
+    (mockAuth.signInWithPassword as jest.Mock).mockResolvedValueOnce({
+      data: { user: { id: "user-1" }, session: { access_token: "tok" } },
+      error: null,
+    });
+    const result = await authenticateUser("user@example.com", "password123");
+    expect(result).toEqual({ ok: true });
+  });
+
+  it("returns network error message on thrown exception", async () => {
+    (mockAuth.signInWithPassword as jest.Mock).mockRejectedValueOnce(
+      new Error("Network request failed")
+    );
+    const result = await authenticateUser("user@example.com", "password123");
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error).toMatch(/network request failed/i);
+  });
+});

jest.config.js

@@ -0,0 +1,13 @@
+const nextJest = require("next/jest");
+
+const createJestConfig = nextJest({ dir: "./" });
+
+const customJestConfig = {
+  testMatch: ["**/__tests__/**/*.test.ts", "**/__tests__/**/*.test.tsx"],
+  testEnvironment: "jest-environment-jsdom",
+  moduleNameMapper: {
+    "^@/(.*)$": "<rootDir>/$1",
+  },
+};
+
+module.exports = createJestConfig(customJestConfig);

jest.setup.ts

@@ -0,0 +1 @@
+import "@testing-library/jest-dom";