Mockito.anyString() crashes with NPE in Kotlin

问题

I am using espresso and I want to create a mock response for the content resolver.

When I use:

`when`(context.activity.contentResolver.query(
        ArgumentMatchers.isA(Uri::class.java), 
        ArgumentMatchers.isA(Array<String>::class.java), 
        ArgumentMatchers.anyString(), null, null))
.thenReturn(matrixCursor)

I get the error:

java.lang.NullPointerException: uri 
at com.android.internal.util.Preconditions.checkNotNull(Preconditions.java:128)

Is it possible to create the mock response for the content resolver in such cases?

回答1:

That looks like a nullability issue. Mockito does not work that well with nullable types in Kotlin.

There is a library that handles this problem: https://github.com/nhaarman/mockito-kotlin

I'd suggest you to check anyOrNull() here and try something like

ArgumentMatchers.anyOrNull<String>(), isNull(), isNull()

Read this article to gain full understanding of the problem and how to handle it any different scenarios.

来源：https://stackoverflow.com/questions/49081875/mockito-anystring-crashes-with-npe-in-kotlin