Glossary

Every concept in this sheet, plus the smaller terms it uses. Select a concept to open its card.

Boundary value analysis: Testing the values at and next to the edges of each partition, where off-by-one mistakes live.
Bug life cycle: The states a bug moves through: new, triaged, in progress, fixed, ready for retest, then closed or reopened.
Bug report: A record of a problem with a clear title, steps to reproduce, expected and actual results, environment details and evidence such as screenshots, logs or a video.

Decision tables: A table listing combinations of conditions and the expected result for each, used when a rule depends on several inputs at once.

Equivalence partitioning: Splitting possible inputs into groups the system should treat the same way, then testing one value from each group.
Exploratory testing: Designing and running tests at the same time, learning as you go, usually in a timed session guided by a charter such as "Explore checkout with expired cards to discover how errors are handled".

Functional and non-functional testing: Functional testing checks what the system does: features, rules and outputs.

Requirements analysis: Reading a user story or specification before any code exists and asking questions: what happens on errors, at limits, with empty input, for which users.
Risk-based testing: Choosing what to test, and how deeply, by the likelihood that an area fails and the impact if it does.

SDLC and STLC: The SDLC is how a team takes a product from idea to release (plan, design, build, test, release, maintain).
Seven testing principles: Widely taught principles: testing shows the presence of defects, not their absence; exhaustive testing is impossible; test early; defects cluster; tests wear out; testing depends on context; and a lack of bugs does not mean the product is useful.
Severity and priority: Severity is how badly the bug affects the system.
Smoke, sanity and regression testing: A smoke test is a quick check that a build works at all.

Test cases and checklists: A test case gives preconditions, steps, test data and an expected result.
Test levels: Unit tests check one small piece of code.
Test management tools: Tools that store test cases, plan test runs, record results and link them to requirements and bugs.
Test pyramid: A model for balancing a suite: many fast unit tests at the bottom, fewer integration and API tests in the middle, and a small number of end-to-end UI tests at the top.

Verification and validation: Verification asks whether the product was built as specified.

Why we test: Testing is running software, or examining its artefacts, to find defects and to give people evidence about its quality so they can decide whether to release it.