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how many repositories repackaged it
536
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on the repository, not the skill itself
Install
one command, takes just this skill from the repository
npx skills add https://github.com/HoangNguyen0403/agent-skills-standard --skill common-tddCopy
What comes with it
8 760 bytes besides the instruction
The instruction itself
11 sections, as written by the author
Test-Driven Development (TDD) Standard
Priority: P0 (CRITICAL) > Iron Law: NO PRODUCTION CODE WITHOUT FAILING TEST FIRST.
> Code written before test MUST deleted. Start over.
Step 1: RGR Loop (Red-Green-Refactor) > [!TIP]
> Orchestration : If sub-agents are available, delegate each AC implementation to specialist-tdd-implementer.
RED : Write minimal failing test. Verify failure (Expected error, not typo).GREEN : Write simplest code to pass. Verify pass .REFACTOR : Clean up code while staying green.
Red Flags
Stop if code exists before test : Delete it. Restart from RED.Stop if test passes first run : You tested old behavior.Stop if "tests after" appears : That is not TDD.
AAA Structure (Mandatory) Every test must follow Arrange-Act-Assert:
Arrange : Set up inputs, stubs, mocks, and expected values.Act : Call single unit under test.Assert : Verify output and side effects. One logical assertion per test.
(See AAA Example for code structure) .
Step 3: Verification & Thresholds
Minimum Coverage : 80% (Stat/Func/Line), 75% (Branch).Mocks :Always mock: HTTP, Time/Date, Filesystem.
Never mock: Fast internal services (<200ms), pure domain logic.
See Test Runner Reference for environment-specific commands.
Step 4: Principles & Mocks
Watch it Fail : Prove test works before writing code.Minimalism : Don't add features/options beyond current test (YAGNI).Isolation : Mock external APIs (HTTP) and Time.Realism : Prefer real DBs (test containers) and fast internal services (<200ms).
Rationalization Prevention
"Too small to test" : Small code still regresses. Write the test."Manual testing is enough" : Manual checks do not prove the RED step."Keep code as reference" : Pre-test code biases the implementation. Delete it."Tests after are equivalent" : Passing immediately proves little.
Verification Checklist
[ ] Every new function/method failing test first?
[ ] Failure message expected?
[ ] Minimal code implemented passed?
[ ] AAA structure followed?
[ ] Coverage thresholds met?
Expert References
AAA Example
AAA Methodology
Test Runners
TDD Patterns
Testing Anti-Patterns
Anti-Patterns
No test-after : Writing tests post-implementation defeats TDD. Delete and restart.No assertion-free tests : test without assert not test.No testing implementation : Test behavior and contracts, not internal calls.
A passing test alone is not enough: the failing test must demonstrate missing behavior before implementation.