Hands-On Lab and Phase Exit TaskFlow - Full Stack Developer 2026
Lab 1 - Pure policy • Write table-driven tests for every allowed and rejected Task status transition.
• Add one deterministic due-date policy test with a fixed clock input.
Lab 2 - Service • Use FakeTaskRepository.
• Prove MEMBER can update an assigned Task.
• Prove a denied transition produces the expected application exception.
Lab 3 - Repository + PostgreSQL • Create two Workspaces and two Tasks.
• Prove listScoped never leaks the unrelated Workspace.
• Prove pagination totalItems is computed inside the same authorization filter.
Lab 4 - HTTP security • 401 without identity.
• 403 or scoped 404 for unauthorized resource/action.
• 400 for invalid DTO.
• 200/201 for valid authorized request.
Lab 5 - Frontend • Form error can be found by accessible text/role.
• TanStack optimistic failure rolls back.
• No shared QueryClient state leaks between tests.
Lab 6 - Browser • Playwright: sign in fixture -> create Task -> update status -> reload -> persisted state.
• Repeat one permission-denied workflow with MEMBER role.
Phase exit checklist • I can explain unit vs integration vs HTTP/e2e vs browser E2E.
• I know when a fake repository is appropriate and when a real database is required.
• I can test authentication/authorization without trusting the browser.
• I can test a React form through accessible interactions rather than internals.
• I can keep TanStack Query tests isolated.
• I can design one critical Playwright journey instead of browser-testing every edge case.
• I understand that coverage is evidence, not correctness.
Sources Source Used for
NestJS Testing Nest 12 uses runner-agnostic testing utilities; new projects use https://docs.nestjs.com/fundamentals/testing Vitest by default and Nest integrates with Supertest for HTTP e2e tests.
Prisma ORM v7 Testing Use a dedicated resettable test database for integration tests; unit https://www.prisma.io/docs/orm/v7/more/best-practices tests should isolate logic from external dependencies.
Prisma Unit Testing Unit testing isolates logic; dependency injection/mocking can keep https://docs.prisma.io/docs/orm/prisma-client/testing/unit-te database calls out of unit suites. sting
Next.js Vitest Next.js documents Vitest + React Testing Library for https://nextjs.org/docs/app/guides/testing/vitest unit/component testing; async Server Components are better covered by E2E.
Next.js Playwright Next.js recommends Playwright for browser end-to-end tests and https://nextjs.org/docs/app/guides/testing/playwright production-like testing.
React Testing Library Tests should resemble how users interact with the UI rather than https://testing-library.com/docs/react-testing-library/intro/ assert implementation details.
TanStack Query Testing Tests should isolate QueryClient instances and avoid shared cache https://tanstack.com/query/latest/docs/framework/react/gui state across tests. des/testing
Playwright Playwright runs Chromium, Firefox and WebKit with isolated https://playwright.dev/docs/browsers browser contexts.
Vitest npm Current stable used in this phase: 5.0.1. https://www.npmjs.com/package/vitest
React Testing Library npm Current stable used in this phase: 16.3.3. https://www.npmjs.com/package/@testing-library/react
Playwright npm Current stable used in this phase: 1.63.0. https://www.npmjs.com/package/@playwright/test
Tests are executable behavioral contracts. Good tests protect meaningful invariants and failure cases, not implementation trivia.
Restate the goal of “Hands On Lab and Phase Exit” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: behavior contract → arrange → act → assert → regression signal. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: Vitest + integration + Playwright test suite with deterministic fixtures and CI-ready commands.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
it("rejects deleting another member's task", async () => {
const response = await asUser(bob).delete(`/tasks/${aliceTask.id}`);
expect(response.status).toBe(403);
expect(await taskStillExists(aliceTask.id)).toBe(true);
});Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Look for shared database state, timers, globals, unordered execution, or missing cleanup before adding retries.
Move the highest-risk boundary to an integration test with the real adapter/database.
Without copying the final source, create a second small scenario that applies “Hands On Lab and Phase Exit” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Write one Playwright flow for a critical user journey and make setup/cleanup reproducible.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.E2E used for every rule, making feedback too slow
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.