Robolectric tests running in Android Studio but not on the command line

Question

I'm trying to run unit tests using Robolectric; they run fine under Android Studio, but the exact same tests fail when running in the command line - which is a big deal, I need to be able to run them from my continuous integration platform, not just from an IDE.

I suspect that I'm missing some command-line argument (say, a classpath or something similar) or calling the wrong task - otherwise the test wouldn't run at all from Android Studio. Some relevant details; the test looks like this:

@RunWith(RobolectricTestRunner.class)
@Config(manifest = "app/src/main/AndroidManifest.xml", resourceDir = "res", emulateSdk = 19)
public class SplashActivityTest {

    @Test
    public void testActivity() {
        SplashActivity splashActivity = new SplashActivity();
        String appName = splashActivity.getString(R.string.app_name); // HERE, line 20
        assertEquals(appName, "App");
    }

}

As mentioned above, it runs fine in Android Studio (by right-clicking the test file and selecting Run 'SplashActivityTest') but when running it from the command line it fails in the line marked with HERE, with the following stack trace:

android.content.res.Resources$NotFoundException: unknown resource 2131492893
  at org.robolectric.shadows.ShadowAssetManager.getAndResolve(ShadowAssetManager.java:309)
  at org.robolectric.shadows.ShadowAssetManager.getResourceText(ShadowAssetManager.java:69)
  at android.content.res.AssetManager.getResourceText(AssetManager.java)
  at android.content.res.Resources.getText(Resources.java:240)
  at org.robolectric.shadows.ShadowResources.getText(ShadowResources.java:361)
  at android.content.res.Resources.getText(Resources.java)
  at android.content.res.Resources.getString(Resources.java:330)
  at org.robolectric.shadows.ShadowContext.getString(ShadowContext.java:39)
  at org.robolectric.shadows.ShadowContextWrapper.getString(ShadowContextWrapper.java:69)
  at android.content.Context.getString(Context.java)
  at path.to.myApp.activities.SplashActivityTest.testActivity(SplashActivityTest.java:20)
  // ... and so on ...

I'm using this to run from the command line (notice that in here and in Android Studio I'm using the Gradle wrapper):

project-root$ ./gradlew test --continue

Also: I'm using Android Studio 1.1.0, Gradle version is 2.3, Robolectric's version is 3.0-SNAPSHOT and Robolectric's Gradle plugin version is 1.0.1

Answer 1

It turns out that this is a known issue. The resources of a project are looked for in the wrong directory when running tests from the command line, here's a link to the issue; for now the workaround is to write a custom test runner as demonstrated here:

public class RobolectricGradleTestRunner extends RobolectricTestRunner {

    public RobolectricGradleTestRunner(Class<?> testClass) throws InitializationError {
        super(testClass);
        String buildVariant = (BuildConfig.FLAVOR.isEmpty() ? "" : BuildConfig.FLAVOR+ "/") + BuildConfig.BUILD_TYPE;
        String intermediatesPath = BuildConfig.class.getResource("").toString().replace("file:", "");
        intermediatesPath = intermediatesPath.substring(0, intermediatesPath.indexOf("/classes"));

        System.setProperty("android.package", BuildConfig.APPLICATION_ID);
        System.setProperty("android.manifest", intermediatesPath + "/manifests/full/" + buildVariant + "/AndroidManifest.xml");
        System.setProperty("android.resources", intermediatesPath + "/res/" + buildVariant);
        System.setProperty("android.assets", intermediatesPath + "/assets/" + buildVariant);
    }

}

The test cases must be updated accordingly to use the custom test runner instead of the @Config annotation:

@RunWith(RobolectricGradleTestRunner.class)
public class SplashActivityTest {
    // tests same as before
}

Also, it's recommended to perform a clean when running the tests from the command line, given that the workaround depends on the contents of the build directory, we don't want to have stale data there:

project-root$ ./gradlew clean test --continue