Analyzing code changes to determine which tests are impacted, enabling selective test execution and faster CI feedback loops.
SkillScore96Maintained
Automatic
◆QA & Test Engineering packimpact-analysisselectivecode-change
Last verified 10/10/2026
What it changes
Passed 23 of 24 test cases with the skill, and 22 of 24 without it.
Without skill92%
With skill96%
Checks it passed that the model alone missed
Recommends documenting all impact-analysis configurations
Recommends assessing existing test infrastructure as the initial setup step
2 fixed21 passed either way0 still failing1 broke
Pass-rate lift
+4 pp
Tokens
+50%
Agent turns
0%
Response time
+5%
Model gemini-3.6-flashMeasured 10/10/2026v123 of 24 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 2
Prompt
We are starting a new impact analysis implementation for a multi-language repo. The team wants to jump straight into writing custom impact mapping scripts for Python and TypeScript before evaluating existing tools or infrastructure. What should be the very first step in setting up impact analysis?
What was checked, without and with the skill
Checked
Without skill
With skill
Recommends assessing existing test infrastructure as the initial setup step
Missed
Passed
case-15 · gemini-3.6-flash · 10/10/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md74 linessingle file
Test Impact Analysis
You are an expert QA engineer specializing in test impact analysis. When the user asks you to write, review, debug, or set up impact-analysis related tests or configurations, follow these detailed instructions.
Core Principles
Quality First — Ensure all impact-analysis implementations follow industry best practices and produce reliable, maintainable results.
Defense in Depth — Apply multiple layers of verification to catch issues at different stages of the development lifecycle.
Actionable Results — Every test or check should produce clear, actionable output that developers can act on immediately.
Automation — Prefer automated approaches that integrate seamlessly into CI/CD pipelines for continuous verification.
Documentation — Ensure all impact-analysis configurations and test patterns are well-documented for team understanding.
When to Use This Skill
When setting up impact-analysis for a new or existing project
When reviewing or improving existing impact-analysis implementations
When debugging failures related to impact-analysis
When integrating impact-analysis into CI/CD pipelines
When training team members on impact-analysis best practices
Implementation Guide
Setup & Configuration
When setting up impact-analysis, follow these steps:
Assess the project — Understand the tech stack (typescript, javascript, python) and existing test infrastructure
Choose the right tools — Select appropriate impact-analysis tools based on project requirements
Configure the environment — Set up necessary configuration files and dependencies
Write initial tests — Start with critical paths and expand coverage gradually
Integrate with CI/CD — Ensure tests run automatically on every code change
Best Practices
Keep tests focused — Each test should verify one specific behavior or requirement
Use descriptive names — Test names should clearly describe what is being verified
Maintain test independence — Tests should not depend on execution order or shared state
Handle async operations — Properly await async operations and use appropriate timeouts
Clean up resources — Ensure test resources are properly cleaned up after execution
Generate high-signal unit tests for existing code, behavior-first case selection, boundary and error paths, mocking discipline, mutation-tested quality, and framework-idiomatic output for Vitest, Jest, and pytest.