Flutter
Flutter golden tests capture a screenshot of a widget and compare it pixel-by-pixel against a reference image (the "golden file"). If the screenshot changes, the test fails. This catches visual regressions — layout shifts, color changes, font differences — that behavioral tests miss entirely. This guide covers writing golden tests,
Angular
Playwright is the recommended E2E testing framework for Angular applications in 2026, replacing the deprecated Protractor. It supports auto-waiting, multi-browser testing, network interception, and trace capture out of the box. This guide covers adding Playwright to an Angular project, writing effective E2E tests, and deciding when to use Angular CDK
TypeScript
TypeScript mocking has one goal: replace real dependencies with test doubles that are fully type-checked. The toolbox includes jest.fn() with generic parameters, jest.Mocked for class/interface mocks, jest.spyOn for partial mocks, and ts-mockito for fluent mock setup. This guide covers each pattern with realistic examples and explains
Vue.js
Cypress component testing runs Vue components in a real browser — not jsdom, not a virtual DOM. This means your CSS is applied, browser APIs work correctly, and user interactions behave exactly as they do in production. Unlike Vitest + Vue Test Utils which runs in Node, Cypress component tests give you
Flutter
The bloc_test package provides blocTest() — a declarative test helper that makes BLoC and Cubit testing concise. You define the initial state, the events/actions to trigger, and the expected state sequence. Compared to manually subscribing to BLoC streams, blocTest() handles stream subscription, async operations, and teardown automatically. Key Takeaways
Vue.js
Testing Vue Router involves three distinct scenarios: testing route guards in isolation (pure functions), testing components that use router composables (useRoute, useRouter), and testing the full router flow with real navigation. Each requires a different approach. This guide covers all three with Vitest and Vue Test Utils 2. Key Takeaways
Angular
Spectator is an Angular testing library that wraps TestBed with a simpler, less verbose API. Instead of 20 lines of configureTestingModule, compileComponents, createComponent, and detectChanges, you get a one-liner factory that handles all of it. This guide covers the full Spectator API: createComponent, createService, SpyObject mocks, and event testing. Key
TypeScript
tRPC procedures are TypeScript functions — they accept typed input, receive a context, and return typed output. The createCaller pattern lets you call tRPC procedures directly in tests without an HTTP server. This gives you full type safety, fast execution, and the ability to inject test contexts (mocked databases, authenticated users)
Flutter
Mocking in Flutter means replacing real dependencies (API clients, database repositories, platform services) with test doubles that you control. Mocktail is the modern choice: it doesn't require code generation, works with null safety out of the box, and has a clean API. Mockito is the alternative — it requires
Vue.js
Pinia stores are plain JavaScript/TypeScript objects — state, getters, and actions — which makes them easy to test directly without mounting Vue components. For unit tests, call setActivePinia(createPinia()) in beforeEach and import your stores normally. For component tests, use createTestingPinia() from @pinia/testing to mount components with full control over
Angular
Angular services are the workhorses of Angular applications — they handle HTTP calls, state management, caching, and business logic. Testing services involves two main concerns: intercepting HTTP requests with HttpClientTestingModule, and isolating service dependencies with spy objects. For complex observable chains, RxJS marble testing gives you frame-level control over timing. This
TypeScript
Zod schemas are code — they contain business logic (required fields, format constraints, cross-field validation) that can break if changed carelessly. Testing Zod schemas means verifying that valid data passes, invalid data fails with the right error messages, and transforms produce the expected output types. This guide covers testing patterns for