---

name: go-testing-helpers description: Test helper patterns with t.Helper()

Test Helpers

Extract common test logic into helper functions with t.Helper().

CORRECT

Copyfunc assertEqual(t *testing.T, got, want interface{}) {
    t.Helper()  // Reports caller line, not helper line
    if got != want {
        t.Errorf("got %v, want %v", got, want)
    }
}

func assertNoError(t *testing.T, err error) {
    t.Helper()
    if err != nil {
        t.Fatalf("unexpected error: %v", err)
    }
}

func Test_Process(t *testing.T) {
    result, err := Process("input")
    assertNoError(t, err)
    assertEqual(t, result, "expected")
}

Why:

• t.Helper() marks function as helper
• Error reports show caller line, not helper line
• Reduces test boilerplate
• Consistent assertion patterns

WRONG

Copyfunc assertEqual(t *testing.T, got, want interface{}) {
    // Missing t.Helper()
    if got != want {
        t.Errorf("got %v, want %v", got, want)
    }
}

Problems:

• Errors point to helper line
• Hard to find actual test failure
• Confusing stack traces