可以分两步运行单个android测试:

you can run the single android test in two steps:

1. ./gradlew installDebugAndroidTest
2. adb shell am instrument -w -e class com.example.MyInstrumentationTest#testFoo com.example.test/android.support.test.runner.AndroidJUnitRunner
   https://developer.android.com/tools/testing/testing_otheride.html