# Test Runner Hook

Automatically run relevant tests when code changes are detected, with intelligent test selection and parallel execution

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## Metadata

**Title:** Test Runner Hook
**Category:** hooks
**Author:** JSONbored
**Added:** September 2025
**Tags:** testing, automation, ci-cd, watch, parallel
**URL:** https://claudepro.directory/hooks/test-runner-hook

## Overview

Automatically run relevant tests when code changes are detected, with intelligent test selection and parallel execution

## Content

KEY FEATURES
? Intelligent test selection based on code changes
? Parallel test execution for faster feedback
? Support for multiple testing frameworks
? Fail-fast mode for quick feedback
? Smart retry for flaky tests
? Impact analysis and dependency mapping
? Integration with CI/CD pipelines
INSTALLATION
CLAUDE CODE:
1) Create hooks directory: mkdir -p .claude/hooks
2) Create hook file: touch .claude/hooks/test-runner-hook.sh
3) Make executable: chmod +x .claude/hooks/test-runner-hook.sh
4) Add configuration from Hook Configuration section above to .claude/settings.json or ~/.claude/settings.json
5) Alternative: Use the interactive /hooks command in Claude Code
Requirements:
? Claude Code CLI installed
? Project directory initialized
CONFIGURATION
Hook Configuration:
Hook Type: postToolUse
 Script: ./.claude/hooks/code-test-runner-hook.sh
 Matchers: write, edit, multiedit
HOOK SCRIPT
#!/usr/bin/env bash
READ THE TOOL INPUT FROM STDIN
INPUT=$(cat)
TOOLNAME=$(echo "$INPUT" | jq -r '.toolname')
FILEPATH=$(echo "$INPUT" | jq -r '.toolinput.filepath // .toolinput.path // ""')
if [ -z "$FILE_PATH" ]; then
 exit 0
fi
echo "🧪 Running tests for $FILE_PATH..."
GET FILE EXTENSION AND DIRECTORY
EXT="${FILE_PATH##*.}"
DIR=$(dirname "$FILE_PATH")
FIND AND RUN RELEVANT TESTS BASED ON FILE TYPE
case "$EXT" in
 js|jsx|ts|tsx)
 # JavaScript/TypeScript files
 if [ -f "package.json" ]; then
 if command -v npm &> /dev/null && npm list jest &> /dev/null; then
 echo "Running Jest tests..."
 npm test -- --testPathPattern="$FILE_PATH" --passWithNoTests 2>/dev/null
 elif command -v npm &> /dev/null && npm list vitest &> /dev/null; then
 echo "Running Vitest tests..."
 npx vitest run "$FILE_PATH" 2>/dev/null
 fi
 fi
 ;;
 py)
 # Python files
 if command -v pytest &> /dev/null; then
 echo "Running pytest..."
 pytest "${FILEPATH%.}test.py" "${DIR}/test_.py" 2>/dev/null || echo "No Python tests found"
 elif command -v python &> /dev/null; then
 echo "Running Python unittest..."
 python -m unittest discover -s "$DIR" -p "test.py" 2>/dev/null || echo "No Python tests found"
 fi
 ;;
 go)
 # Go files
 if command -v go &> /dev/null; then
 echo "Running Go tests..."
 go test "${DIR}/..." 2>/dev/null || echo "No Go tests found"
 fi
 ;;
 java)
 # Java files
 if command -v mvn &> /dev/null && [ -f "pom.xml" ]; then
 echo "Running Maven tests..."
 mvn test 2>/dev/null
 elif command -v gradle &> /dev/null && [ -f "build.gradle" ]; then
 echo "Running Gradle tests..."
 gradle test 2>/dev/null
 fi
 ;;
esac
echo "✅ Test execution completed for $FILE_PATH" >&2
exit 0
USE CASES
? Automated testing in CI/CD pipelines
? Real-time test feedback during development
? Intelligent test selection for large codebases
? Parallel test execution for faster builds
? Pre-commit test validation
TROUBLESHOOTING
1) Tests run on every file save slowing down
 Solution: Add file extension filter or test file detection: if [[ "$FILEPATH" == test ]] || [[ "$FILEPATH" == spec ]]; then exit 0; fi to skip running tests when editing test files themselves.
2) Jest testPathPattern not finding related tests
 Solution: Pattern matches test file paths not source. Use --findRelatedTests instead: npm test -- --findRelatedTests="$FILE_PATH" which finds tests importing the changed file through dependency graph.
3) Hook runs tests twice with both Jest and Vitest
 Solution: Detection uses npm list jest which may find both. Add explicit priority: if npm list jest &> /dev/null; then run_jest; exit 0; elif npm list vitest ... to prevent fallthrough.
4) Python tests fail to locate test directory
 Solution: Hook looks for ${FILEPATH%.}test.py and test_.py. For pytest, use explicit discovery: pytest --collect-only "$DIR" 2>/dev/null | grep "test session starts" to verify test detection.
5) Go tests timeout on large module changes
 Solution: Add timeout flag and scope: go test -timeout 30s "${DIR}" 2>/dev/null instead of ${DIR}/... which tests all subpackages. Or use go test -short for quick tests only during development.
TECHNICAL DETAILS
Documentation: https://jestjs.io/docs/getting-started


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Source: Claude Pro Directory
Website: https://claudepro.directory
URL: https://claudepro.directory/hooks/test-runner-hook

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