Flutter Mockito Package Cheat Sheet

Introduction

This article is all about the possibilities of mocking that the Mockito package provides. We’ll look into setting up mocks, verifying the calls, and pitfalls to avoid.

I recently published an article about mocking in unit tests with the Mockito package in Flutter apps.

How to Mock Dependencies in your Flutter App for Testing

Here is a tutorial on how to create mocks with the mockito package, set them up, and use them in your tests of a Flutter application.

This follow-up article is a cheat sheet for you to quickly find an example of how to use the package. I also updated the GitHub repository of the original post and it now contains the cheat sheet as a working test class.

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Final tips

✅ Always use thenAnswer(), never use thenReturn() ▶ Explanation
✅ If you verify a mock, the invocation counter is reset!
✅ If there are multiple matching setups, the last setup wins!

Source code

You can find the source code on GitHub.

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