JUnit Test Android library with Robolectric: java.lang.InstantiationException

Question

When I try to run the JUnit test in an Android library project with Robolectric, I get the following error:

java.lang.RuntimeException: java.lang.InstantiationException at com.xtremelabs.robolectric.ApplicationResolver.newApplicationInstance(ApplicationResolver.java:56) at com.xtremelabs.robolectric.ApplicationResolver.resolveApplication(ApplicationResolver.java:36) at com.xtremelabs.robolectric.RobolectricTestRunner.createApplication(RobolectricTestRunner.java:246) at com.xtremelabs.robolectric.RobolectricTestRunner.setupApplicationState(RobolectricTestRunner.java:233) at com.xtremelabs.robolectric.RobolectricTestRunner.internalBeforeTest(RobolectricTestRunner.java:177) at com.xtremelabs.robolectric.RobolectricTestRunner.methodBlock(RobolectricTestRunner.java:157) at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: java.lang.InstantiationException at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at java.lang.Class.newInstance0(Unknown Source) at java.lang.Class.newInstance(Unknown Source) at com.xtremelabs.robolectric.ApplicationResolver.newApplicationInstance(ApplicationResolver.java:54) ... 20 more 

My first idea was that I made a mistake in the test, so I simplified the test run as much as possible:

 import static org.junit.Assert.*; import org.junit.Test; import org.junit.runner.RunWith; import com.xtremelabs.robolectric.RobolectricTestRunner; @RunWith(RobolectricTestRunner.class) public class CommonDataTest { @Test public void test(){ assertTrue(true); } } 

but I still get the same error. I created the project as described here: http://robolectric.org/eclipse-quick-start/ It is strange that it worked with other projects in the Android Library without any problems.

Any help would be appreciated! Thank you in advance!

Answer 1

it seemed Robolectric was unable to create an application from my library, so I replaced TestRunner:

 import org.junit.runners.model.InitializationError; import android.app.Application; import com.xtremelabs.robolectric.RobolectricTestRunner; public class MyTestRunner extends RobolectricTestRunner { public MyTestRunner(Class<?> testClass) throws InitializationError { super(testClass); } @Override protected Application createApplication() { return new Application() { }; } } 

and used it instead of RobolectricTestRunner:

 @RunWith(MyTestRunner.class) 

Now the tests run correctly.