Source identity:

ddx:
  id: resource.google-test-sizes

Google Testing Blog: Test Sizes

Source

• URL: https://testing.googleblog.com/2010/12/test-sizes.html
• Accessed: 2026-05-12

Summary

Google’s Testing Blog describes small, medium, and large tests as a practical way to distinguish test scope. Small tests are isolated and fast, medium tests exercise limited integration such as a database or localhost service, and large tests exercise broader system behavior. The guidance emphasizes isolation, parallel execution, and using test size to organize suites.

Relevant Findings

• Test levels should be defined by scope and dependencies, not only by tool.
• Isolation and bounded dependencies make tests faster and less flaky.
• Large tests are valuable but should be fewer, slower, and focused on critical end-to-end paths.
• Naming test size lets teams enforce different expectations in CI.

HELIX Usage

This resource informs the Test Plan artifact. HELIX uses it to define test levels, infrastructure needs, sequencing, and CI gates in a way that agents can apply consistently before implementation begins.

Authority Boundary

This resource supports test-scope planning. It does not replace project-specific coverage targets, acceptance criteria, or Story Test Plans.