Software Testing

Why Testing Matters Code Runs; Software Needs Proof Writing code that compiles is only half the job. Software must behave correctly under real conditions: strange input, ...

The Testing Pyramid Balance the Test Portfolio Not all tests are born equal. Unit tests are fast and cheap; end-to-end tests are slow and brittle. The testing pyramid is a model ...

Writing Test Cases and Test Plans From Requirement to Test Case A test case is a single, precise check of one behavior. Good test cases are written before they are automated, and ...

Unit Testing with JUnit Verifying a Single Unit A unit test verifies one function or class in isolation, feeding it controlled inputs and checking the outputs. JUnit is the ...

Integration Testing Where Units Meet Unit tests prove each piece works alone. Integration tests prove the pieces work together: a service class writing to a real (or near-real) ...

End-to-End Testing Through the User's Eyes End-to-end (E2E) tests drive the full running application exactly as a user would: opening a browser, clicking buttons, filling forms, ...

Test-Driven Development Red, Green, Refactor Test-Driven Development (TDD) flips the usual order: write the test before the code. The rhythm is a loop of three stages. Red means ...

Mocking and Test Doubles Isolating the Unit Under Test Units often depend on other things: a database, an email service, a clock, a third-party API. Testing against the real ...

Regression and Performance Testing Old Bugs Coming Back A regression is a bug that returns after an unrelated change. The classic story: an upgrade to fix one thing silently ...

CI and Automated Testing Runs Every Time, Right Away Automated tests only pay off when they actually run, and the best place is a CI pipeline that runs them on every push. CI ...