Test-Driven Development Skill

Enforce TDD for every implementation task. This skill ensures quality throughtests first.

Workflow

Step 1 — Write Failing Test

• Identify the smallest unit of behavior
• Write test that fails because feature doesn't exist
• Use language-specific testing framework
• Keep test focused and simple

Step 2 — Write Minimal Code

• Implement only what's needed to pass test
• No optimization yet
• No additional features
• Get to green quickly

Step 3 — Refactor

• Clean up code while tests pass
• Improve structure, names, organization
• Ensure tests still pass
• No new functionality

Testing Patterns by Language

Go

func TestUnitName(t *testing.T) {
    t.Run("should do thing", func(t *testing.T) {
        // arrange
        input := ...
        expected := ...

        // act
        result := DoThing(input)

        // assert
        assert.Equal(t, expected, result)
    })
}

TypeScript

describe('UnitName', () => {
  it('should do thing', () => {
    const input = ...;
    const expected = ...;

    const result = doThing(input);

    expect(result).toEqual(expected);
  });
});

C++

TEST_F(UnitNameTest, ShouldDoThing) {
    auto input = ...;
    auto expected = ...;

    auto result = doThing(input);

    EXPECT_EQ(expected, result);
}

Quality Gates

• All tests must pass before commit
• Coverage ≥ 80% for new code
• No flaky tests
• Fast execution (< 30s for unit tests)