tdd

Original：🇺🇸 English

Translated

Test-driven development with strict RED-GREEN-REFACTOR enforcement. Enforces: write failing test first, minimal implementation, then refactor. Use when adding new features or fixing bugs.

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Sourcescando1993/sugar

Added on2026-04-28

NPX Install

npx skill4agent add scando1993/sugar tdd

SKILL.md Content

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Test-Driven Development

Iron Law

NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

Cycle

RED — Write a failing test

Write a test that defines the expected behavior BEFORE writing any production code.

The test MUST fail before you write production code
If the test passes without any changes, your test is wrong — rewrite it
The test should describe behavior, not implementation

GREEN — Write the minimum production code

Write the minimum production code to make the test pass.

Do NOT write more than necessary
Do NOT optimize
Do NOT refactor
Ugly code that passes is correct at this stage

REFACTOR — Clean up without changing behavior

Improve the code while keeping all tests green.

All tests must still pass after refactoring
Improve naming, extract functions, remove duplication
If any test fails after refactoring, your refactor changed behavior — revert

Red Flags — If You Catch Yourself Thinking:

Thought	Reality
"I'll write the implementation first, then add tests"	That's not TDD. Write the test FIRST.
"This is too simple to test"	If it's too simple to test, it's simple enough to test quickly.
"I'll write all the tests first, then implement"	One test at a time. RED-GREEN-REFACTOR. One cycle.
"The test is basically the same as the implementation"	Then you're testing implementation, not behavior. Rewrite the test.

Rules

ONE test at a time, ONE cycle at a time
NEVER skip RED — if the test doesn't fail first, it proves nothing
NEVER skip REFACTOR — clean code is part of the deliverable
Commit after each GREEN (passing test + minimal implementation)

tdd