Issue
Where can I find the source code for ActivityTestRule?
Solution
You can find it at https://android.googlesource.com/platform/frameworks/testing/+/android-support-test/rules/src/main/java/android/support/test/rule/ActivityTestRule.java
You have to use branch android-support-test instead of master on platform/frameworks/testing project in AOSP.
Answered By – Yenchi