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AgentCompany/builtin-skills/software-engineer/clean-code/references/test-first-law.md
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ZacharyZhang-NY e74dafcd36 Silence render-disposed spam, unbreak bundled skills, drop board wake
Three independently ugly bugs that all fed the same log flood:

* Electron's `WebFrameMain.send` writes every "Render frame was disposed"
  to stderr via `console.error`. When the worker fans a second
  agent-event past a reloading renderer, we produced thousands of
  identical lines and stalled the main loop on stderr I/O. Added a
  `mainFrame.detached` guard so the send is short-circuited before
  Electron's own catch block fires, and installed a targeted filter in
  `suppress-warnings.ts` (now actually imported from the entry point)
  so the specific `console.error("Error sending from webFrameMain:"…)`
  noise never reaches the terminal. Any other payload still surfaces.

* `dispatchAgentMessage` accepted the human-reader sentinel as a wake
  target when an agent replied to `__board__` — `wakeAgentIfPossible`
  then called `db.getAgent("__board__")`, threw, and the dispatcher
  kept repeating on every send. Strip `HUMAN_SENDER_ID` at
  `resolveMessageWakeTargets`, and keep a defense-in-depth guard in the
  heartbeat so a stray caller (future automation fan-out) cannot
  reintroduce the crash.

* Pi's skills loader rejects any SKILL.md whose frontmatter `name`
  diverges from its parent directory. The four bundled `my-writing-style`
  copies declared `name: writing-style-skill`, so every install emitted
  a warning and dropped the skill. They also lived as orphan gitlinks
  (mode 160000 without .gitmodules), and the global `*.md` gitignore
  hid every other SKILL.md from version control. Fixed the frontmatter
  to match the dir, converted the dangling submodules to plain trees,
  and allowlisted `builtin-skills/**/*.md` so a fresh clone carries the
  catalogue instead of silently losing it.
2026-04-20 08:13:48 -04:00

1.7 KiB

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Follow the Three Laws of TDD MEDIUM achieves 90%+ test coverage naturally test, tdd, first, laws

Follow the Three Laws of TDD

Test-Driven Development follows three rules: (1) Write a failing test before production code, (2) Write only enough test to fail, (3) Write only enough production code to pass. This cycle repeats.

Incorrect (writing tests after code):

// Production code written first, then tests added later (or never)
public class Calculator {
    public int add(int a, int b) {
        return a + b;
    }

    public int divide(int a, int b) {
        return a / b;  // Edge cases not considered
    }
}

// Test written after - may not cover edge cases
@Test
public void testAdd() {
    assertEquals(4, calculator.add(2, 2));
}
// No test for divide by zero because code was written first

Correct (TDD cycle):

// 1. Write failing test first
@Test
public void divideShouldReturnQuotient() {
    assertEquals(2, calculator.divide(6, 3));
}

// 2. Write minimal code to pass
public int divide(int a, int b) {
    return a / b;
}

// 3. Write next failing test
@Test(expected = IllegalArgumentException.class)
public void divideShouldThrowOnDivideByZero() {
    calculator.divide(6, 0);
}

// 4. Update code to pass
public int divide(int a, int b) {
    if (b == 0) {
        throw new IllegalArgumentException("Cannot divide by zero");
    }
    return a / b;
}

Benefits:

  • Tests cover requirements, not implementation
  • Edge cases discovered through test-first thinking
  • High coverage achieved naturally

Reference: Clean Code, Chapter 9: Unit Tests