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
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.
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.
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) } The newest solution with java 17 (I guess it helps from java 11 but didn't test it)
Just follow the steps:
1.Add the universal methods to your code
fun setStaticFieldViaReflection(field: Field, value: Any) { field.isAccessible = true getModifiersField().also { it.isAccessible = true it.set(field, field.modifiers and Modifier.FINAL.inv()) } field.set(null, value) } fun getModifiersField(): Field { return try { Field::class.java.getDeclaredField("modifiers") } catch (e: NoSuchFieldException) { try { val getDeclaredFields0: Method = Class::class.java.getDeclaredMethod( "getDeclaredFields0", Boolean::class.javaPrimitiveType ) getDeclaredFields0.isAccessible = true val fields = getDeclaredFields0.invoke(Field::class.java, false) as Array<Field> for (field in fields) { if ("modifiers" == field.name) { return field } } } catch (ex: ReflectiveOperationException) { e.addSuppressed(ex) } throw e } } 2.Add these flags to gradle (it can be changed for other java classes)
android { ... testOptions { unitTests.all { jvmArgs( "--add-opens", "java.base/java.lang=ALL-UNNAMED", "--add-opens", "java.base/java.lang.reflect=ALL-UNNAMED" ) } } } 3.Examples of using
//SDK_INT setStaticFieldViaReflection(Build.VERSION::class.java.getDeclaredField("SDK_INT"), 30) //SOC_MANUFACTURER private val testSocManufacturer = "test-soc-manufacturer" setStaticFieldViaReflection(Build::class.java.getDeclaredField("SOC_MANUFACTURER"), testSocManufacturer) //SOC_MODEL private val testSocModel = "test-soc-model" setStaticFieldViaReflection(Build::class.java.getDeclaredField("SOC_MODEL"), testSocModel) Thanks Sergei for the JDK 17 solution. A more Kotlin-ish function for Step #1 of Sergei's answer:
private fun getModifiersField(): Field = try { Field::class.java.getDeclaredField("modifiers") } catch (e: NoSuchFieldException) { try { val getDeclaredFields0: Method = Class::class.java.getDeclaredMethod("getDeclaredFields0", Boolean::class.javaPrimitiveType) getDeclaredFields0.isAccessible = true @Suppress("unchecked_cast") (getDeclaredFields0.invoke(Field::class.java, false) as Array<Field>).first { it.name == "modifiers" } } catch (ex: ReflectiveOperationException) { e.addSuppressed(ex) throw e } } We recently came across this issue at work. We created a function and in our unit tests we just mocked it. Problem was that we lost the linter and on one release we had an issue that we never caught due to the linter. Anyways, we tried the reflection on JAVA 17 and it worked like a charm, but the moment we started testing all of the unit tests we had so many issues. For example, if 1 unit test that touched the reflection failed for whatever reason (even forcing an exception or Assert.fail("error")) then it caused a lot of random tests to fail. Then we thought, we could deal with that, but then another test was switched over and the reflection caused an issue with another mock and it failed no matter what. So after fighting with chatgpt for hours yesterday and today, we got a nice modified solution that works with the linter. We ended up doing something like this:
fun androidSdkVersionAtLeastQ() = Build.VERSION.SDK_INT > Build.VERSION_CODES.Q @RequiresApi(Build.VERSION_CODES.Q) fun qFun() { //api q } if (androidSdkVersionGreaterThan(Build.VERSION_CODES.Q)) { qFun() } So basically for each API that each part of the code requires you create a function for it and just mock it in your unit test
I hope this helps anybody. the last 2 days were hell, but we had been fighting with this for months, at least a year, on a good solution and now this is just perfect.
You could use
@Config(sdk = [31]) from Robolectric
