# Testing Pyramid
Confidence: high
Last verified: 2026-05-22
Generation: ai_assisted


## TL;DR

The Testing Pyramid (Mike Cohn) describes the optimal distribution of test types: many fast unit tests at the base, fewer integration tests in the middle, few slow E2E tests at the top. The Anti-Pattern: inverted pyramid (ice cream cone) — many E2E tests, few unit tests.

## Core Explanation

Unit tests: test individual functions/components in isolation, milliseconds, run on every commit. Integration tests: test multiple units together (API + DB), seconds. E2E tests: test full user flows through browser (Cypress, Playwright), minutes, run on deploy. Coverage metrics: line, branch, function — 100% coverage ≠ bug-free. Test behavior, not implementation.

## Further Reading

- [Succeeding with Agile (Mike Cohn)](https://www.mountaingoatsoftware.com/books/succeeding-with-agile)