| commit | c3e6182c327825249f721d003c0295caf57d55ad | [log] [tgz] |
|---|---|---|
| author | Niek Haarman <haarman.niek@gmail.com> | Tue Jul 26 21:28:30 2016 +0200 |
| committer | Niek Haarman <haarman.niek@gmail.com> | Tue Jul 26 21:28:30 2016 +0200 |
| tree | c6c8122cc6ba82e545e2ad6fbf87e37f9c94d924 | |
| parent | 6867394348875e7fbb1bee193ccbf9dfcc16892b [diff] |
Specify explicit return types for Mockito calls.
A small library that provides helper functions to work with Mockito in Kotlin.
Mockito-Kotlin is available on JCenter. For Gradle users, add the following to your build.gradle:
repositories { jcenter() } dependencies { testCompile "com.nhaarman:mockito-kotlin:x.x.x" }
Due to Kotlin‘s reified type parameters, if the type can be inferred, you don’t have to specify it explicitly:
Java:
MyClass c = mock(Myclass.class); c.doSomething(mock(MyOtherClass.class));
Kotlin:
val c : MyClass = mock() c.doSomething(mock())
If the type can't be inferred, you can pass it like so:
val d = mock<MyClass>()
Mockito‘s any(Class<T>) often returns null for non-primitive classes. In Kotlin, this can be a problem due to its null-safety feature. This library creates non-null instances when necessary. Again, if the type can be inferred, you don’t have to specify it explicitely:
Java:
verify(myClass).doSomething(any(String.class));
Kotlin:
verify(myClass).doSomething(any()); // Non-nullable parameter type is inferred
For generic arrays, use the anyArray() method:
verify(myClass).setItems(anyArray())
There are some cases where Mockito-Kotlin cannot create an instance of a class. This can for instance be when a constructor has some specific preconditions for its parameters. You can register instance creators to overcome this:
MockitoKotlin.registerInstanceCreator<MyClass> { MyClass(5) }
Whenever MockitoKotlin needs to create an instance of MyClass, this function is called, giving you ultimate control over how these instances are created.
These instance creators work on a per-file basis: for each of your test files you will need to register them again.
Using higher-order functions, you can write very clear expectations about expected values. For example:
Kotlin:
verify(myClass).setItems(argThat{ size == 2 })
Most of Mockito‘s static functions are available as top-level functions. That means, IDE’s like IntelliJ can easily import and autocomplete them, saving you the hassle of manually importing them.