Instruction file imported from lam-vd/workflow-kit (.github/instructions/testing.instructions.md). Copyright stays with the author.

Testing Rules

Pyramid

• Unit (many): pure logic, branches, edge cases.
• Integration (medium): module + DB + external mocks.
• E2E (few): happy path + 1–2 critical user flows.

Naming

• Test names describe behavior, NOT implementation.
• Format: should <expected behavior> when <condition>.
• Example: should return 400 when email is empty.

Structure (AAA)

// Arrange
const input = ...
// Act
const result = sut(input)
// Assert
expect(result).toBe(...)

Coverage targets

• Domain layer: ≥ 90%.
• Application: ≥ 80%.
• Infrastructure: smoke + contract tests.
• UI: critical flows via e2e.

Mocking

• Mock at boundaries (HTTP, DB, time, randomness) — DO NOT mock domain.
• Avoid complex mock chains; if needed → refactor production code.

Edge case checklist (per business-logic function)

• Empty / null / undefined input
• Boundary values (0, max int, empty array, single element)
• Concurrent / race conditions (if async)
• Error paths from dependencies
• i18n / unicode / timezone

Anti-patterns (flag 🟠)

• Tests dependent on execution order.
• Tests using real network / real DB without cleanup.
• Tests with if/else inside test logic (split into separate tests).
• expect(true).toBe(true) or placeholder asserts.
• Meaningless test names (test1, should work).