CODEWITHSUNDEEP
androidunit-testingkotlinjunitmockito
Sumit Sharma
Sumit Sharma

Reputation: 251

How to use Mockito.mockStatic for mocking static methods in kotlin android

How to use Mockito.mockStatic for mocking static methods in kotlin android ?

This is my code:

    class MyUtilClassTest {
       @Test
       fun testIsEnabled() {
          Mockito.mockStatic(MyUtilClass::class.java, Mockito.CALLS_REAL_METHODS)
                .use { mocked ->
                    mocked.`when`<Boolean> { MyUtilClass.isEnabled() }.thenReturn(true)
                    assertTrue(MyUtilClass.isEnabled())
                }
       }
    }
    
    object MyUtilClass {
       fun isEnabled(): Boolean = false
    }

I am getting this exception:

org.mockito.exceptions.misusing.MissingMethodInvocationException: when() requires an argument which has to be 'a method call on a mock'. For example: when(mock.getArticles()).thenReturn(articles);

Also, this error might show up because:

  1. you stub either of: final/private/equals()/hashCode() methods. Those methods cannot be stubbed/verified. Mocking methods declared on non-public parent classes is not supported.
  2. inside when() you don't call method on mock but on some other object.

Upvotes: 16

Views: 12034

Answers (2)

nuhkoca
nuhkoca

Reputation: 1943

If you annotate your function isEnabled with @JvmStatic, you won't get any error. As @Neige pointed out, static functions in Kotlin are actually not static in bytecode by default. Therefore, we need to mark our function with @JvmStatic in order to generate additional static getter/setter methods.

object MyUtilClass {
   @JvmStatic
   fun isEnabled(): Boolean = false
}

Upvotes: 7

Neige
Neige

Reputation: 2840

From the JVM point of view MyUtilClass.isEnabled() is not a static class/function. You can use Show Kotlin Bytecode to understand what is behind

public final class MyUtilClass {
   public static final MyUtilClass INSTANCE;

   public final boolean isEnabled() {
      return false;
   }

   private MyUtilClass() {
   }

   static {
      MyUtilClass var0 = new MyUtilClass();
      INSTANCE = var0;
   }
}

Upvotes: 2

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