Resources$NotFoundException when running Roboelectric test

Question

I've just set up Roboelectric 3.2.2 with a new app and I have written my first simple test:

@RunWith(RobolectricTestRunner.class)
@Config(manifest="src/main/AndroidManifest.xml",
    packageName="my.pacakge.name.debug")
public class MainActivityTest {

    @Test
    public void clickButton() {
        MainActivity mainActivity = Robolectric.setupActivity(MainActivity.class);
        String text = ((TextView)mainActivity.findViewById(R.id.text_main)).getText().toString();
        assertEquals("Should equal Hello World!", "Hello World!", text);
    }
}

I've followed all the set up and instructions here and here but I am still getting this error every time I try to run the test:

android.content.res.Resources$NotFoundException: Unable to find resource ID #0x0 in packages [android, my.package.name.debug]

This exception occurs at the first line of the test where I am calling setupActivity().

Answer 1

It worked for me: add @Config(manifest = "src/main/AndroidManifest.xml")

@Config(manifest = "src/main/AndroidManifest.xml")
@RunWith(RobolectricTestRunner.class)
public class MainActivityTest {

    @Test
    public void testSomething() throws Exception {
        assertTrue(Robolectric.setupActivity(MainActivityTest .class) != null);
    }
}   

Note 1: If you are still getting the same error (happens when creating new project)

The Reason is related to different working directory & the answer is here: https://stackoverflow.com/a/31469526/4802664

Note 2: Using

Android Studio 3.0 (canary 9)
Gradle 4.1
Android Gradle plugin 3.0.0-alpha9
robolectric: 3.4.2

Gradle

buildscript {

    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0-alpha9'
    }
}    

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'


    testImplementation 'junit:junit:4.12'

    // Espresso
    androidTestImplementation 'com.android.support.test:runner:1.0.0'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.0'

    // Robolectric
    testImplementation 'org.hamcrest:hamcrest-library:1.3'
    testImplementation 'org.robolectric:robolectric:3.4.2'
}

Answer 2

This plugin works for me when using custom RobolectricTestRunner and provide the missing system properties.

public class CustomRobolectricTestRunner extends RobolectricTestRunner {

  public CustomRobolectricTestRunner(Class<?> testClass) throws InitializationError {
    super(testClass);
    String buildVariant = BuildConfig.BUILD_TYPE + (BuildConfig.FLAVOR.isEmpty()? "" : "/" + BuildConfig.FLAVOR);
    System.setProperty("android.package", BuildConfig.APPLICATION_ID);
    System.setProperty("android.manifest", "build/intermediates/manifests/full/" + buildVariant + "/AndroidManifest.xml");
    System.setProperty("android.resources", "build/intermediates/res/" + buildVariant);
    System.setProperty("android.assets", "build/intermediates/assets/" + buildVariant);
  }
}

Edit: You must also use a different working directory at your unit test run configuration. Best is to change the default configuration and use $MODULE_DIR$ https://code.google.com/p/android/issues/detail?id=158015#c5