Getting DexException when running assembleDebugAndroidTest goal second time about android-test-kit

[GoogleCodeExporter]

I get this running "connectedCheck" as well.

OS X 10.10.3

Gradle 2.4
Rules 0.3
Runner 0.3
Espresso-Core 2.2

Running a clean first prevents the issue. 

UNEXPECTED TOP-LEVEL EXCEPTION:
com.android.dex.DexException: Multiple dex files define 
Landroid/app/BuildConfig;
    at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
    at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
    at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
    at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
    at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
    at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:454)
    at com.android.dx.command.dexer.Main.runMonoDex(Main.java:303)
    at com.android.dx.command.dexer.Main.run(Main.java:246)
    at com.android.dx.command.dexer.Main.main(Main.java:215)
    at com.android.dx.command.Main.main(Main.java:106)

:app:dexDevDebugAndroidTest FAILED

Original comment by [email protected] on 8 Jun 2015 at 5:50

[GoogleCodeExporter]

I think that I was able to fix my issue by removing productFlavors which reset 
my applicationId. 

Previously we had no default applicationId, and two flavors that each set their 
own applicationId. I changed that to setting a default value, and then an 
applicationIdSuffix for our dev builds - and the problem went away. 

Original comment by [email protected] on 8 Jun 2015 at 10:27

[GoogleCodeExporter]

This seems like a Gradle issue, does a ./gradlew clean fix it when this error 
occurs?

Original comment by [email protected] on 9 Jun 2015 at 2:49

[GoogleCodeExporter]

Yes. A clean fixes it until the next time you try to run the tests.

Original comment by [email protected] on 9 Jun 2015 at 3:08