Writing maintainable tests

Alright, so after a decade-plus in Ruby, I've gotten into some great debates about testing with colleagues. Through these conversations, I've come up with a testing style that's not exactly textbook, but it's been doing the job and doing it well. Good to get this down for my own clarity and future reference.

Anatomy of my ideal test

Here's a structured blueprint of how I craft my tests:

it 'provides a succinct description of the behavior' do
  setup
  exercise
  verify
  teardown
end

Key Characteristics

  • Verbose: Each test is self-explanatory, serving as its documentation.

  • State isolation: Avoid shared global state to prevent entanglement.

  • Four-step structure: The tests follow the Setup, Exercise, Verify, Teardown paradigm.

  • Co-location: All four steps reside within the same block.

  • Visual clarity: Steps are demarcated with empty lines for easier navigation.

Rationale

Modularity for future changes

In my observation, most test modifications are constrained to specific portions of the test file. This isolation eliminates the need to refactor unrelated tests, ensuring that changes are smooth and swift.

Avoiding shared state

Shared states in tests invite two vices: mutability and coupling. They often lead to complex setups and tear-downs that become increasingly harder to manage as your codebase evolves.

Advocacy for verbosity

Tests aren't just tests; they are documentation. A verbose test provides more context, aiding in both readability and maintainability.

Explicit test steps

Each of the four steps —Setup, Exercise, Verify, Teardown— is designed to be semantically clear. This separation enhances readability, serving as a reliable guide through complex test scenarios.

Concluding remarks

While Ruby’s philosophy often emphasizes principles like DRY (Don't Repeat Yourself), I've found that a different mindset is necessary for testing. Duplication is fine in this case in favor of an optimal test case isolation. I feel confident that this testing approach delivers a strong return on investment.