I'm trying to use the new multidex option but I get the following error:
Execution failed for task ':packageAll[Variant]TestClassesForMultiDex'.
> java.util.zip.ZipException: duplicate entry: android/support/multidex/BuildConfig.class
I've been able to discover the issue only happens when running the connectedAndroidTests task, and not when simply building the project (build).
There's an issue for this, and it's resolved in multi-dex library 1.0.1, see: Duplicate BuildConfig classes when using multidex test support
Try:
compile 'com.android.support:multidex:1.0.1'
androidTestCompile 'com.android.support:multidex-instrumentation:1.0.1'