managing-vitest

name	managing-vitest
description	Use when working with Vitest — vitest testing framework management and analysis. Covers test suite configuration, coverage reporting, snapshot management, benchmark analysis, workspace setup review, and Vite-native test features. Use when managing Vitest test suites, investigating test failures, reviewing code coverage, or analyzing test performance.
connection_type	vitest
preload	false

Vitest Testing Framework Management Skill

Manage and analyze Vitest test suites, coverage, and configurations.

Core Helper Functions

#!/bin/bash

# Run Vitest with JSON reporter
vitest_run() {
    local args="${1:-}"
    npx vitest run $args --reporter=json 2>/dev/null
}

MANDATORY: Discovery-First Pattern

Always discover Vitest configuration and test structure before querying specifics.

Phase 1: Discovery

#!/bin/bash

echo "=== Vitest Configuration ==="
if [ -f "vitest.config.ts" ]; then
    grep -E "(include|exclude|coverage|environment|globals|setupFiles|testTimeout)" vitest.config.ts | head -15
elif [ -f "vite.config.ts" ]; then
    grep -A 20 "test:" vite.config.ts | head -20
fi

echo ""
echo "=== Vitest Version ==="
npx vitest --version 2>/dev/null

echo ""
echo "=== Test File Summary ==="
find . -name "*.test.ts" -o -name "*.test.tsx" -o -name "*.spec.ts" -o -name "*.spec.tsx" 2>/dev/null | grep -v node_modules | wc -l | xargs echo "Total test files:"
find . -name "*.test.ts" -o -name "*.spec.ts" 2>/dev/null | grep -v node_modules | head -15

echo ""
echo "=== Workspace Configuration ==="
if [ -f "vitest.workspace.ts" ] || [ -f "vitest.workspace.js" ]; then
    cat vitest.workspace.* | head -15
else
    echo "No workspace configuration found (single project)"
fi

Phase 2: Analysis

#!/bin/bash

echo "=== Last Test Run Results ==="
REPORT="test-results.json"
if [ -f "$REPORT" ]; then
    cat "$REPORT" | jq '{
        total: .numTotalTests,
        passed: .numPassedTests,
        failed: .numFailedTests,
        skipped: .numPendingTests,
        suites: .numTotalTestSuites,
        duration_sec: (.startTime as $s | now - ($s / 1000) | floor)
    }'

    echo ""
    echo "=== Failed Tests ==="
    cat "$REPORT" | jq -r '
        .testResults[] | select(.status == "failed") |
        "\(.name | split("/") | last)\t\(.message | split("\n")[0])"
    ' | column -t | head -15
fi

echo ""
echo "=== Coverage Summary ==="
if [ -f "coverage/coverage-summary.json" ]; then
    cat coverage/coverage-summary.json | jq '.total | {
        lines: "\(.lines.pct)%",
        branches: "\(.branches.pct)%",
        functions: "\(.functions.pct)%",
        statements: "\(.statements.pct)%"
    }'
fi

echo ""
echo "=== Benchmark Results ==="
find . -name "*.bench.ts" -o -name "*.bench.js" 2>/dev/null | grep -v node_modules | head -5

Output Rules

• TOKEN EFFICIENCY: Target 50 lines per output
• Parse JSON reporter output for structured results
• Never dump full snapshots — show diffs only

Anti-Hallucination Rules

• NEVER guess test file names — always discover via filesystem
• NEVER fabricate coverage numbers — parse actual coverage-summary.json
• NEVER assume Vitest config location — check vitest.config., vite.config.

Safety Rules

• NEVER update snapshots without explicit user confirmation
• NEVER modify test or config files without user approval
• NEVER delete coverage reports without user consent

Output Format

Present results as a structured report:

Managing Vitest Report
══════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative