Testing Flashcards

Which testing technique checks boundary values at the edges of input ranges?

Answer: Boundary value analysis

Boundary value analysis tests values at the minimum, maximum, and just inside/outside the boundaries of valid input ranges.

In Jest, what does the `beforeEach` hook do?

Answer: Runs before each individual test in a describe block

`beforeEach` executes a setup function before every individual test (`it`/`test`) within its scope.

What is a test double that records calls and allows assertions on how it was used?

Answer: Spy

A spy wraps a real function and records information about its calls (arguments, return values, call count) for later assertions.

Which HTTP status code range should a REST API return when a client sends an invalid request that fails validation?

Answer: 4xx

4xx status codes indicate client-side errors; 400 Bad Request or 422 Unprocessable Entity are typical for validation failures.

What does `screen.getByRole('button', { name: /submit/i })` test in React Testing Library?

Answer: That a button is accessible with the text 'submit' using ARIA roles

React Testing Library's `getByRole` queries the DOM using ARIA roles and accessible names, promoting accessibility-first testing.

Which tool is commonly used to measure code coverage in a Node.js/Jest project?

Answer: Istanbul (nyc)

Istanbul (also known as nyc) is the code coverage tool integrated into Jest by default via `--coverage`.

What is the purpose of contract testing in a microservices architecture?

Answer: To verify that services agree on the API shape they expect from each other

Contract testing (e.g., with Pact) ensures that a consumer's expectations of a provider's API match what the provider actually delivers.