Question 1

What are the most common unit testing pitfalls?

Accepted Answer

Common unit testing pitfalls include brittle tests, poor test coverage, slow execution, excessive mocking, and tightly coupling tests to implementation details.

Question 2

Why do unit tests become brittle over time?

Accepted Answer

Unit tests become brittle when they depend on internal implementation details, hard-coded data, or unstable dependencies that frequently change.

Question 3

How does poor test coverage affect software quality?

Accepted Answer

Poor test coverage increases the risk of defects reaching production, reduces confidence in code changes, and weakens overall software quality.

Question 4

What problems are caused by slow unit tests?

Accepted Answer

Slow unit tests delay feedback in CI/CD pipelines, reduce developer productivity, and discourage frequent test execution.

Question 5

How can excessive mocking harm unit tests?

Accepted Answer

Excessive mocking can hide real defects, reduce test readability, and create false confidence by masking integration issues.

Question 6

Why is test isolation important in unit testing?

Accepted Answer

Test isolation ensures each unit test runs independently, preventing shared state and external dependencies from causing inconsistent results.

Question 7

How can flaky unit tests be avoided?

Accepted Answer

Flaky unit tests can be avoided by removing timing dependencies, using deterministic test data, mocking external systems correctly, and maintaining test isolation.

Question 8

What role does CI/CD play in identifying unit testing pitfalls?

Accepted Answer

CI/CD pipelines run unit tests on every commit, helping teams quickly identify flaky tests, performance bottlenecks, and coverage gaps.

Question 9

How should unit tests be maintained as the codebase grows?

Accepted Answer

Unit tests should be refactored alongside production code, reviewed regularly, and kept simple to remain maintainable over time.

Question 10

How do good unit testing practices support higher-level testing?

Accepted Answer

Strong unit testing practices catch defects early and provide a stable foundation for integration and end-to-end testing.