Test coverage in Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is test coverage in Flutter testing?

Test coverage measures how much of your app's code is executed when tests run. It helps you see which parts of your code are tested and which are not.

beginner

Why is high test coverage important?

High test coverage means more code is checked by tests, reducing bugs and making your app more reliable and easier to maintain.

intermediate

How do you generate a test coverage report in Flutter?

Run flutter test --coverage in your project folder. This creates a coverage file showing which lines of code were tested.

intermediate

What file format does Flutter use for coverage reports?

Flutter generates coverage reports in lcov.info format, which can be viewed with tools like lcov or online coverage viewers.

advanced

Can 100% test coverage guarantee a bug-free app?

No. 100% coverage means all code runs during tests, but tests must also check correct behavior. Coverage shows tested code, not test quality.

Which command generates a test coverage report in Flutter?

A flutter test --coverage

B flutter build coverage

C flutter analyze coverage

D flutter run --coverage

The correct command to generate coverage data is flutter test --coverage.

What does test coverage measure?

A How many tests you wrote

B How fast tests run

C How many bugs tests find

D How much code runs during tests

Test coverage measures how much of your code is executed when tests run.

Which file contains Flutter's coverage report data?

A lcov.info

B coverage.json

C coverage.txt

D report.xml

Flutter outputs coverage data in the lcov.info file.

Does 100% test coverage mean your app has no bugs?

A Yes, always

B Only if tests are written in Dart

C No, coverage shows tested code but not test quality

D Only if tests run fast

100% coverage means all code runs during tests, but tests must also check correct behavior to catch bugs.

Why should you check test coverage regularly?

A To make tests run slower

B To find untested code that might have bugs

C To reduce app size

D To increase app startup time

Checking coverage helps find code not tested, which might hide bugs.

Explain what test coverage is and why it matters in Flutter app development.

Think about how much of your code your tests actually run.

Describe the steps to generate and view a test coverage report in Flutter.

Start with running tests with coverage enabled.