Testing Flashcards
7 cards from real Web Development practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Testing flashcards as text
What is 'snapshot testing' as used in Jest?
Answer: Serializing a component's rendered output and comparing it to a stored reference on future runs
Jest snapshot testing serializes a component's output (often JSX/HTML) into a `.snap` file and fails if the output changes unexpectedly.
Which Playwright locator is most resistant to CSS/styling changes when targeting elements?
Answer: .getByRole('button', { name: 'Submit' })
Role-based locators use ARIA semantics rather than visual attributes, making them resilient to style changes and better for accessibility.
What is the purpose of `afterAll` in Jest?
Answer: Runs a cleanup function once after all tests in the describe block complete
`afterAll` runs a teardown function exactly once after all tests in its scope have finished, useful for closing database connections or servers.
In load testing, what does 'throughput' measure?
Answer: The number of requests processed per unit of time
Throughput measures how many requests (or transactions) a system can handle per second, indicating its processing capacity.
What is the difference between a 'mock' and a 'stub' in testing terminology?
Answer: Mocks verify behavior (expectations); stubs provide canned responses without assertions
Stubs return pre-configured responses to make tests work, while mocks additionally assert that specific interactions occurred (they are pre-programmed with expectations).
Which of the following correctly describes a 'regression test'?
Answer: A test that verifies previously working functionality still works after a code change
Regression tests guard against old bugs reappearing by re-verifying that existing functionality remains intact after new changes.
What does `supertest` help you test in a Node.js application?
Answer: HTTP endpoints by making requests against an Express/Koa app without starting a live server
Supertest allows you to make HTTP assertions against an Express (or similar) app instance directly in your tests without binding to a network port.
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