Integration vs unit test decision in Express - Quick Revision & Key Differences

Recall & Review

beginner

What is a unit test in Express?

A unit test checks a small part of your Express app, like a single function or middleware, in isolation without involving other parts or external systems.

beginner

What does an integration test do in Express?

An integration test checks how different parts of your Express app work together, like routes, middleware, and database calls, to ensure they cooperate correctly.

intermediate

When should you choose a unit test over an integration test?

Choose a unit test when you want to quickly check a small piece of code without external dependencies, making tests fast and easy to fix if broken.

intermediate

Why are integration tests important in Express apps?

Integration tests catch problems that happen when parts of the app interact, like route handlers calling the database, which unit tests alone might miss.

intermediate

What is a key sign you need an integration test in Express?

If your feature depends on multiple parts working together, like middleware, routes, and database, you need an integration test to check the full flow.

Which test focuses on a single function without external systems?

A Performance test

B Unit test

C End-to-end test

D Integration test

Unit tests isolate one function or module, ignoring external parts.

What does an integration test in Express usually include?

A Multiple parts like routes and database working together

B Only one middleware function

C Just the database queries

D Only front-end UI

Integration tests check how different parts like routes and database interact.

When is a unit test preferred over an integration test?

A When testing the whole app flow

B When testing user interface

C When testing network speed

D When testing a small isolated function

Unit tests are best for small, isolated pieces of code.

Which test type is slower but checks more parts working together?

A Integration test

B Unit test

C Static code analysis

D Linting

Integration tests involve multiple components and take longer to run.

What is a sign you should write an integration test in Express?

A Testing a single helper function

B Testing CSS styles

C Testing route handling with database calls

D Testing a math calculation

Integration tests are needed when routes interact with databases or other services.

Explain the main difference between unit tests and integration tests in Express.

Think about testing one piece vs testing how pieces connect.

Describe a situation in an Express app where you would choose an integration test instead of a unit test.

Consider when parts depend on each other.