Unit Test
A unit test checks one small piece of software by itself. Slow or unreliable outside systems are kept out of the test.
Another example
A developer tests a price function with a tax table and several example values. The totals must be exact without starting a network or database. A test that starts the whole service and a real database is not a unit test.
Main parts
- 01unit under test
- 02controlled dependency
- 03focused assertion
Use it when
Use this term for a fast, local check of one behavior with controlled dependencies.
Do not use it when
Do not fake the behavior that the test must check. A unit test cannot prove that the whole system works together.
Name used in code
arrange → act → assert Before you ship
Check the environment and prepared test data (fixture). Define a result you can observe, failure and edge cases, isolation, stable inputs, useful error details, and cleanup. Set a time budget, owner, and flaky-test rule.
Outcome: Use Unit Test to gather repeatable evidence about this behavior or quality risk. User context: A developer tests a price function with a tax table and several example values. The totals must be exact without starting a network or database. A test that starts the whole service and a real database is not a unit test. Validation approach: Unit Test. Why it fits: Use this term for a fast, local check of one behavior with controlled dependencies. Do not use it when: Do not fake the behavior that the test must check. A unit test cannot prove that the whole system works together. Test requirements: Name the system and test environment. Define prepared test data, other inputs, and the result you can observe. Include failure and edge cases, allowed error, isolation, and cleanup. Test operations: Make failures easy to diagnose. Control random or changing inputs. Name an owner. Keep the test fast and simple enough for its release gate. Acceptance criteria: The test fails for the known bug and passes after the fix. It repeats in the target environment, gives useful evidence, and does not expose or change unrelated data. Evidence and limits (evidence boundary): It is official for that source. Other platforms or teams may use the term in another way. Unknowns to confirm: Release gate, environment, prepared test data, allowed error, time budget, owner, and flaky-test rule.
Check this request
Review the current use of Unit Test. Definition: A unit test checks one small piece of software by itself. Slow or unreliable outside systems are kept out of the test. Release checks: Check the environment and prepared test data (fixture). Define a result you can observe, failure and edge cases, isolation, stable inputs, useful error details, and cleanup. Set a time budget, owner, and flaky-test rule. Before changing code, report the evidence you found, gaps, severity, and the smallest safe fix.