Rust Test Fix

Rust Test-Fix-Cycle Skill

Automated Rust testing workflow that runs tests, analyzes failures, suggests fixes, and re-runs to verify.

Overview

This skill streamlines the Rust testing workflow by automating the red-green-refactor cycle:

1. Run tests in a specific crate or workspace
2. Analyze failures using Rust-specific pattern matching
3. Suggest fixes based on common Rust idioms and error patterns
4. Apply fixes automatically or with confirmation
5. Re-run tests to verify the fix
6. Report results with before/after comparison

When to Use

• After writing new Rust code that needs testing
• When fixing failing tests in CI/CD
• During TDD red-green-refactor cycles
• Debugging async/tokio runtime issues
• Fixing type mismatches and borrow checker errors

Usage

# Run in current crate
/rust-test-fix

# Specify crate
/rust-test-fix components

# Specific test
/rust-test-fix components::test_pipeline_integration

# Workspace-wide
/rust-test-fix --workspace

# Auto-fix mode (applies fixes without confirmation)
/rust-test-fix --auto-fix

# Dry run (show fixes but don't apply)
/rust-test-fix --dry-run

Common Patterns Detected

1. Runtime Issues

• Missing #[tokio::test] attribute
• Attempting async operations without runtime
• Fix: Add #[tokio::test] or wrap in tokio::runtime::Runtime

2. Type Mismatches

• std::time::Duration vs chrono::Duration
• Comparing incompatible types
• Fix: Extract to variable with correct type, use proper conversion

3. Borrow Checker

• Mutable reference conflicts
• Moving values in closures
• Fix: Use Arc<Mutex<T>> or Arc<AtomicT> for shared mutable state

4. Environment Variables

• Unsafe std::env::set_var in tests
• Fix: Use temp_env crate or fixture isolation

5. Assertion Failures

• Logic errors in test expectations
• Wrong assertion type
• Fix: Correct assertion logic or use appropriate assertion macro

Example Output

=== Rust Test-Fix Cycle ===
Crate: components
Running tests...

❌ FAILED: test_retry_with_mutable_state
Error: cannot assign to immutable variable `counter`

Analysis:
- Pattern: Shared mutable state in async test
- Cause: Variable `counter` needs to be mutable across spawned tasks
- Solution: Use Arc<AtomicUsize> for thread-safe mutable counter

Suggested Fix:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
-  let counter = 0;
+  let counter = Arc::new(AtomicUsize::new(0));

-  counter += 1;
+  counter.fetch_add(1, Ordering::SeqCst);
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Apply fix? [Y/n]: y

Applying fix... ✓
Re-running tests...

✅ PASSED: test_retry_with_mutable_state

Summary:
- Tests run: 1
- Failures fixed: 1
- Success rate: 100%

Integration

With DevLoop Pipeline

• Automatically detects which crates have recent changes
• Prioritizes tests for modified code
• Uses pipeline metrics to guide test selection

With TDD Workflow

• Integrates with /tdd:tdd-cycle for full TDD workflow
• Supports red-green-refactor phases
• Tracks test coverage improvements

With CI/CD

• Can be run in CI pipeline for automated fixes
• Generates fix reports for PR reviews
• Exports metrics for test quality tracking

Configuration

Set environment variables to customize:

# Test timeout (seconds)
TEST_TIMEOUT=300

# Auto-fix mode (skip confirmation)
AUTO_FIX=true

# Verbosity
RUST_TEST_FIX_VERBOSE=true

# Test arguments
CARGO_TEST_ARGS="--no-fail-fast"

Advanced Features

Pattern Learning

The skill learns from your fixes and suggests similar patterns:

# Save a fix pattern
/rust-test-fix --save-pattern

# List saved patterns
/rust-test-fix --list-patterns

# Apply custom pattern
/rust-test-fix --pattern=tokio-runtime-missing

Batch Mode

Fix multiple test failures in one run:

# Fix all failing tests in crate
/rust-test-fix components --batch

# Fix up to N tests
/rust-test-fix --batch --limit=5

Report Generation

Generate detailed fix reports:

# Markdown report
/rust-test-fix --report=markdown > test-fixes.md

# JSON for CI
/rust-test-fix --report=json > test-fixes.json

Tips

• Run after pulling changes to catch integration issues
• Use --dry-run first to preview fixes
• Combine with /dev:review-code for comprehensive quality check
• Save common patterns for your project
• Review auto-fixes before committing

Examples

Pipeline Test Fixes (Recent Session)

Based on your recent work fixing pipeline tests:

# Fix the retry test with atomic counter
/rust-test-fix eddos::test_retry_with_mutable_state
→ Detected: Mutable state in async context
→ Applied: Arc<AtomicUsize> pattern
→ ✅ Test passed

# Fix git watcher test isolation
/rust-test-fix components::test_git_watcher_creation
→ Detected: Environment assumption
→ Applied: Temp directory pattern
→ ✅ Test passed

# Fix integration test duration types
/rust-test-fix components::test_pipeline_partial_batch_flush
→ Detected: std::time::Duration vs chrono::Duration mismatch
→ Applied: Explicit chrono::Duration usage
→ ✅ Test passed