✅ test: login action test

Author: Xaohs

frontend/src/pages/login/login.action.test.ts

@@ -0,0 +1,90 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { login } from "~/api/auth.ts";
+import { loginAction } from "~/pages";
+
+vi.mock("~/api/auth.ts", () => ({
+  login: vi.fn(),
+}));
+
+vi.mock("react-router", async () => {
+  const actual = await vi.importActual("react-router");
+  return {
+    ...actual,
+    redirect: vi.fn((path: string) => ({ type: "redirect", location: path })),
+  };
+});
+
+describe("loginAction", () => {
+  const mockFormData = new FormData();
+  const mockRequest = (url = "http://localhost/login") =>
+    new Request(url, {
+      method: "POST",
+      body: mockFormData,
+    });
+
+  beforeEach(() => {
+    mockFormData.set("username", "testuser");
+    mockFormData.set("password", "testpass");
+    vi.clearAllMocks();
+  });
+
+  it("calls login with correct arguments", async () => {
+    (login as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce({});
+
+    await loginAction({ request: mockRequest(), params: {}, context: {} });
+
+    expect(login).toHaveBeenCalledWith(
+      "testuser",
+      "testpass",
+      expect.any(AbortSignal),
+    );
+  });
+
+  it("redirects to '/' by default after successful login", async () => {
+    (login as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce({});
+
+    const result = await loginAction({
+      request: mockRequest(),
+      params: {},
+      context: {},
+    });
+
+    expect(result).toEqual({ type: "redirect", location: "/" });
+  });
+
+  it("redirects to 'next' query param if present", async () => {
+    (login as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce({});
+
+    const result = await loginAction({
+      request: mockRequest("http://localhost/login?next=/dashboard"),
+      params: {},
+      context: {},
+    });
+
+    expect(result).toEqual({ type: "redirect", location: "/dashboard" });
+  });
+
+  it("returns error JSON if login fails", async () => {
+    const mockErrorResponse = new Response(
+      JSON.stringify({ error: "Invalid credentials" }),
+      {
+        status: 401,
+        headers: { "Content-Type": "application/json" },
+      },
+    );
+
+    (login as unknown as ReturnType<typeof vi.fn>).mockImplementationOnce(
+      () => {
+        throw mockErrorResponse;
+      },
+    );
+
+    const result = await loginAction({
+      request: mockRequest(),
+      params: {},
+      context: {},
+    });
+
+    expect(result).toEqual({ error: "Invalid credentials" });
+  });
+});