Stub value of Build.VERSION.SDK_INT in Local Unit Test

Question

I am wondering if there is anyway to stub the value of Build.Version.SDK_INT? Suppose I have the following lines in the ClassUnderTest:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
    //do work
}else{
    //do another work
}

How can I cover all the code ?

I mean I want to run two tests with different SDK_INT to enter both blocks.

Is it possible in android local unit tests using Mockito/PowerMockito?

Thanks

loshkin · Accepted Answer · 2019-12-11T09:45:35.030

31

Change the value using reflection.

 static void setFinalStatic(Field field, Object newValue) throws Exception {
    field.setAccessible(true);

    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

    field.set(null, newValue);
 }

And then

 setFinalStatic(Build.VERSION.class.getField("SDK_INT"), 123);

It is tested. Works.

Update: There is a cleaner way to do it.

Create an interface

interface BuildVersionProvider {

    fun currentVersion(): Int

}

Implement the interface

class BuildVersionProviderImpl : BuildVersionProvider {

    override fun currentVersion() = Build.VERSION.SDK_INT

}

Inject this class as a constructor argument through the interface whenever you want current build version. Then in the tests when creating a SUT (System Under Test) object. You can implement the interface yourself. This way of doing things may be more code but follows the SOLID principles and gives you testable code without messing with reflection and system variables.

edited Dec 11 '19 at 09:45

answered Jun 28 '16 at 11:02

loshkin

1,553
2
20
35

That will not work because getField() expects for variable name and Build.VERSION.SDK_INT is actually a value. – Evgeniy Mishustin Jun 28 '16 at 11:07
3

setFinalStatic(Build.VERSION.class.getField("SDK_INT"), "123"); If this doesn't work maybe PowerMockito over mockito and mock the static field. – loshkin Jun 28 '16 at 11:30
amazing - used similar for Build.VERSION.CODENAME setFinalStatic(Build.VERSION.class.getField("CODENAME"), "DEBUG"); – galaxigirl Dec 21 '16 at 11:09
This worked perfectly for me. Just be sure to reset this value after you are finished testing. I am doing this in the @After method of my unit test so other classes are not affected. – fawaad Oct 19 '17 at 16:01
1

@toshkinl How did you manage to remove the precompiler error `Call requires Api level 26 (current min is: 24)`? It only vanishes, if I use `Build.VERSION.SDK_INT` directly. It remains, if I use a wrapper. – ASP Mar 09 '20 at 15:56
@ASP import java.lang.reflect.Field; import java.lang.reflect.Modifier; There is no Android code that requires any API levels. – loshkin Mar 09 '20 at 16:01

score 9 · Answer 2 · answered Apr 05 '18 at 09:22

As an alternative to reflection, you can use your own class that checks for API and then use Mockito to test the API-Dependent logic in fast JVM unit tests.

Example class

import android.os.Build

class SdkChecker {

    fun deviceIsOreoOrAbove(): Boolean = Build.VERSION.SDK_INT >= Build.VERSION_CODES.O

}

Example tested method

fun createNotificationChannel(notificationManager: NotificationManager) {
    if (sdkChecker.deviceIsOreoOrAbove()) { // This sdkChecker will be mocked
        // If you target Android 8.0 (API level 26) you need a channel
        notificationManager.createNotificationChannel()
    }
}

Example unit tests

import com.nhaarman.mockito_kotlin.mock
import com.nhaarman.mockito_kotlin.verify
import com.nhaarman.mockito_kotlin.verifyZeroInteractions
import com.nhaarman.mockito_kotlin.whenever

@Test
fun createNotificationChannelOnOreoOrAbove() {
    whenever(mockSdkChecker.deviceIsOreoOrAbove()).thenReturn(true)

    testedClass.createNotificationChannel(mockNotificationManager)

    verify(mockNotificationManager).createNotificationChannel()
}

@Test
fun createNotificationChannelBelowOreo() {
    whenever(mockSdkChecker.deviceIsOreoOrAbove()).thenReturn(false)

    testedClass.createNotificationChannel(mockNotificationManager)

    verifyZeroInteractions(mockNotificationManager)
}

Stub value of Build.VERSION.SDK_INT in Local Unit Test

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