Quickly solve Mocking with Kotlin
Recently I started tests for my complete project with Kotlin and I came across the “Mockito cannot mock/spy because : final class” problem because by default all classes in Kotlin are final.
This is not a new problem and a lot of people from the community have posted various blogs and answers regarding this problem (as shown below).
Existing solutions: MockMaker
Mockito solved the “cannot mock” problem in v2, by creating a file named org.mockito.plugins.MockMaker and placing this under the resources/mockito-extensions
Easy Peasy Solution
In this article, I just quickly want to introduce you to the easy way to solve the problem.
Just change your Mockito Gradle dependency from the Mockito core:
testImplementation "org.mockito:mockito-core:$mockito_version"to the following:
testImplementation "org.mockito:mockito-inline:$mockito_version"TADA….it’s solved!
Extra
Use Mockito-Kotlin library which provides some helper functions to make the Kotlin code much more concise and idiomatic.
Source: https://github.com/nhaarman/mockito-kotlin
Example
Before:
mock(FeedRepository::class.java)With Mockito-Kotlin:
mock<FeedRepository>()Final thoughts
I hope this article helped you quickly solve the mocking problem with Kotlin and help you focus on testing.
