tdd-rust

# RTK TDD Workflow Enforce Red-Green-Refactor for all RTK filter development. ## The Loop ``` 1. RED — Write failing test with real fixture 2. GREEN — Implement minimum code to pass 3. REFACTOR — Clean up, verify still passing 4. SAVINGS — Verify ≥60% token reduction 5. SNAPSHOT — Lock output format with insta ``` ## Step 1: Real Fixture First Never write synthetic test data. Capture real command output: ```bash # Capture real output from the actual command git log -20 > tests/fixtures/git_log_raw.txt cargo test 2>&1 > tests/fixtures/cargo_test_raw.txt cargo clippy 2>&1 > tests/fixtures/cargo_clippy_raw.txt gh pr view 42 > tests/fixtures/gh_pr_view_raw.txt # For commands with ANSI codes — capture as-is script -q /dev/null cargo test 2>&1 > tests/fixtures/cargo_test_ansi_raw.txt ``` Fixture naming: `tests/fixtures/<command>_raw.txt` ## Step 2: Write the Test (Red) ```rust #[cfg(test)] mod tests { use super::*; use insta::assert_snapshot; fn count_tokens(s: &str) -> usize { s.split_whitespace().count() } // Test 1: Output format (snapshot) #[test] fn test_filter_output_format() { let input = include_str!("../tests/fixtures/mycmd_raw.txt"); let output = filter_mycmd(input).expect("filter should not fail"); assert_snapshot!(output); } // Test 2: Token savings ≥60% #[test] fn test_token_savings() { let input = include_str!("../tests/fixtures/mycmd_raw.txt"); let output = filt...