feat(auth): add signUpUseCase (test red until DI lands)

packages/auth/src/application/use-cases/sign-up.use-case.test.ts

@@ -0,0 +1,47 @@
+import { beforeEach, describe, expect, it } from "vitest";
+import { authContainer } from "@/di/container";
+import { AUTH_SYMBOLS } from "@/di/symbols";
+import { MockUsersRepository } from "@/infrastructure/repositories/mock-users.repository";
+import { MockAuthenticationService } from "@/infrastructure/services/mock-authentication.service";
+import type { IUsersRepository } from "@/application/repositories/users-repository.interface";
+import type { IAuthenticationService } from "@/application/services/authentication-service.interface";
+import { AuthenticationError } from "@/entities/errors";
+import { signUpUseCase } from "./sign-up.use-case";
+
+describe("signUpUseCase", () => {
+  let usersRepo: MockUsersRepository;
+  let authService: MockAuthenticationService;
+
+  beforeEach(() => {
+    if (authContainer.isBound(AUTH_SYMBOLS.IUsersRepository)) {
+      authContainer.unbind(AUTH_SYMBOLS.IUsersRepository);
+    }
+    if (authContainer.isBound(AUTH_SYMBOLS.IAuthenticationService)) {
+      authContainer.unbind(AUTH_SYMBOLS.IAuthenticationService);
+    }
+    usersRepo = new MockUsersRepository();
+    authService = new MockAuthenticationService(usersRepo);
+    authContainer
+      .bind<IUsersRepository>(AUTH_SYMBOLS.IUsersRepository)
+      .toConstantValue(usersRepo);
+    authContainer
+      .bind<IAuthenticationService>(AUTH_SYMBOLS.IAuthenticationService)
+      .toConstantValue(authService);
+  });
+
+  it("creates a new user and returns session + cookie + user", async () => {
+    const result = await signUpUseCase({
+      username: "carol",
+      password: "secret_password",
+    });
+    expect(result.user.username).toBe("carol");
+    expect(result.session.userId).toBe(result.user.id);
+    expect(result.cookie.name).toBe("session");
+  });
+
+  it("throws AuthenticationError when username taken", async () => {
+    await expect(
+      signUpUseCase({ username: "alice", password: "secret_password" }),
+    ).rejects.toBeInstanceOf(AuthenticationError);
+  });
+});