Rust Testing (cargo test)

Guides agents through executing, isolating, and debugging Rust unit tests, integration tests (tests/), and documentation tests using cargo test.

1. Purpose

Execute and debug Rust tests. A "Unit Test" resides in src/ annotated with #[test]. An "Integration Test" resides in tests/.

2. When to Use

Use this skill when:

• Running Rust test suites (cargo test).
• Filtering by test function name (cargo test <name>).
• Viewing stdout in passing or failing tests (cargo test -- --nocapture).

3. When Not to Use

• Do not use for linting; use rust-clippy-check.

4. Required Inputs

• test_name: Name or substring of the test to run.

5. Missing-Input Behavior

1. If test_name is missing: run all tests in package via cargo test.
2. Never comment out assert_eq! to hide test failures.

6. Procedure

Follow these numbered actions:

1. Action 1: Run Targeted Test
   • Execute: cargo test <test_name> -- --nocapture
2. Action 2: Inspect Panic or Assertion Message
   • Read panic trace (left: X, right: Y).
3. Action 3: Trace and Modify Source Code
   • Edit source logic to satisfy test contract.
4. Action 4: Re-Run Targeted Test
   • Confirm test <name> ... ok.
5. Action 5: Run Full Test Suite
   • Execute cargo test.

7. Decision Rules

• If testing expected panics: annotate with #[should_panic(expected = "message")].
• For integration tests: run cargo test --test <integration_test_file>.

8. Output Format

Emit the report using this template:

### Rust Test Report: [Test Name]

- **Command**: `cargo test [test_name]`
- **Status**: [ok | FAILED]
- **Passed**: [Count] | **Failed**: [Count]

#### Resolution Notes
- [Root cause and fix description]

9. Verification Checklist

• cargo test exits with code 0.
• No assertions commented out.
• Compiler warnings addressed.

10. Common Failures and Recovery

11. Stop or Escalation Conditions

Stop and ask the user when:

• Tests require external C libraries (linking errors).

12. Examples

Example 1: Successful Execution

Input:

Test: test_parse_header

Output:

### Rust Test Report: test_parse_header

- **Command**: `cargo test test_parse_header -- --nocapture`
- **Status**: ok
- **Passed**: 1 | **Failed**: 0

#### Resolution Notes
- Fixed off-by-one slice index in header parser.

Example 2: Ambiguous or Missing Input

Input:

Test rust.

Output:

### Rust Test Report: Running Full Suite

- **Command**: `cargo test`
- **Status**: ok
- **Passed**: 12 | **Failed**: 0

Example 3: Expected Final Output

Output:

### Rust Test Report: test_token_expiration

- **Command**: `cargo test test_token_expiration`
- **Status**: ok
- **Passed**: 1 | **Failed**: 0