Android Unit Testing - method to test returning null

Question

Method to test:

public static String getDeviceName() {
    String manufacturer = Build.MANUFACTURER;
    String model = Build.MODEL;
    if (model.startsWith(manufacturer)) {
        return WordUtils.capitalize(model);
    } else {
        return WordUtils.capitalize(manufacturer) + " " + model;
    }
}

test case:

@Test
public void testGetDeviceName() throws Exception {
    String deviceNameTest = "device name";
    assertEquals(deviceNameTest, DeviceUtil.getDeviceName());
}

Error

java.lang.NullPointerException

getDeviceName(DeviceUtil.java:15) DeviceUtilTest.testGetDeviceName(DeviceUtilTest.java:18)

DeviceUtil.getDeviceName() -> returns null

something like this: Genymotion Samsung Galaxy S8 - 7.0.0 - API 24 - 1440x2960 — Renz Manacmol, Oct 19 '17 at 05:41
You need to debug your test case, it seems that you are missing something in your utility class. Could you also send your util classes? — Oguz Ozcan, Oct 19 '17 at 05:41
on test class: Build.MANUFACTURER and Build.MODEL returns null — Renz Manacmol, Oct 19 '17 at 05:52

score 2 · Accepted Answer · answered Oct 19 '17 at 07:17

2

You can not test getDeviceName(), Build.MANUFACTURER and Build. MODEL will return null. Also manufacturer and model are from device, how your IDE can get it?

BTW if you want to test Util class with static method, i suggest you to use PowerMock as well or you have to create wrapper class of util for testing.

answered Oct 19 '17 at 07:17

kimkevin

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read this https://stackoverflow.com/questions/32074356/how-to-android-unit-test-and-mock-a-static-method – kimkevin Oct 19 '17 at 07:19
@SkyWalker no problem. normally I create wrapper class of util class for testing. – kimkevin Oct 19 '17 at 07:43

score 0 · Answer 2 · answered Mar 07 '21 at 19:30

You can just set the value of the android.os.Build.MANUFACTURER and android.os.Build.MODEL in your test with thee following code:

ReflectionHelpers.setStaticField(android.os.Build::class.java, "MANUFACTURER", "My Manufacturer")
ReflectionHelpers.setStaticField(android.os.Build::class.java, "MODEL", "My Model ")

Find below the full piece of code.

@TestInstance(TestInstance.Lifecycle.PER_CLASS)
internal class DeviceInfoManagerImplTest{
    private lateinit var manager: DeviceInfoManagerImpl
    private lateinit var context: Context
    private lateinit var firebaseTokenManager: FirebaseManager
    private lateinit var dispatchers: CoroutineDispatchers

    @BeforeAll
    fun setUp(){
        context = mockk(relaxed = true)
        firebaseTokenManager= mockk()
        dispatchers = spyk()
        manager = DeviceInfoManagerImpl(context,
                firebaseTokenManager,
                dispatchers)

        coEvery { dispatchers.io } returns
                CoroutineDispatchersImpl().io

        coEvery { firebaseTokenManager.getToken() } returns "token"
        ReflectionHelpers.setStaticField(android.os.Build::class.java, "MANUFACTURER", "My Manufacturer")
        ReflectionHelpers.setStaticField(android.os.Build::class.java, "MODEL", "My Model ")

        mockkStatic(Settings.Secure::class)

        every {
            Settings.Secure.getString(context.contentResolver,
                    Settings.Secure.ANDROID_ID)
        } answers {
            "My ID"
        }
    }

    @Test
    fun test(){
        val deviceInfo = runBlocking { manager.getDeviceInfo() }
        println(deviceInfo.deviceManufacturer)
        println(deviceInfo.deviceUniqueIdentification)
    }
}

Android Unit Testing - method to test returning null

2 Answers2