Unit testing in Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is unit testing in Flutter?

Unit testing in Flutter means checking small parts of your app, like a single function, to make sure they work correctly by themselves.

beginner

Which package is commonly used for writing unit tests in Flutter?

The test package is used to write unit tests in Flutter. It provides tools to define and run tests.

beginner

What does the test() function do in Flutter unit testing?

The test() function defines a single test case. You give it a description and a function that contains the code to check.

intermediate

Why should unit tests be fast and isolated?

Unit tests should be fast so you can run them often without waiting. They should be isolated to test only one thing at a time, avoiding side effects.

beginner

What is the role of the expect() function in Flutter unit tests?

The expect() function checks if a value matches what you expect. It compares actual results with expected results to pass or fail the test.

Which Flutter package is used to write unit tests?

A test

B flutter_test

C http

D provider

The 'test' package is the core package for writing unit tests in Flutter.

What does the test() function require as arguments?

A A description string and a callback function

B Only a callback function

C Only a description string

D A widget and a callback function

The 'test()' function needs a description and a function that contains the test code.

What is the purpose of the expect() function?

A To run the test

B To define a test group

C To check if a value matches the expected result

D To mock dependencies

The 'expect()' function compares actual and expected values to determine test success.

Why should unit tests be isolated?

A To test multiple features at once

B To avoid side effects and test only one thing

C To slow down the testing process

D To depend on external services

Isolation ensures tests do not affect each other and focus on a single unit.

Which of these is NOT a characteristic of good unit tests?

A Fast execution

B Isolated from other tests

C Repeatable with same results

D Dependent on network calls

Good unit tests should NOT depend on network calls to remain fast and reliable.

Explain how to write a simple unit test in Flutter using the test package.

Think about the basic structure: import, test definition, and checking results.

Why is it important to keep unit tests isolated and fast? Give an example.

Imagine testing a calculator function vs. testing a network call.