Android Studio Firebase Test Lab Infrastructure Failure: Internal error during validation

Question

I am facing issues running Android Instrumented Tests on Firebase Test Lab. I am doing it for educational purposes. Is there something wrong with my configuration? I am using the Spark Plan and have billing enabled on my project.

Testing started at 8:06 AM ...
Using Cloud Storage Bucket location test-lab-bq18y48ujt1ma-jytyvif64vc0m/as-build_2020-09-04_08:06:47.708_ndiJ ...
Uploading app APK ...
Uploading test APK ...
Submitting tests to Firebase Test Lab ...
Validating APKs ...

You can also view test results, along with other runs against this app, on the web:
 

Nexus 4, LG, Virtual | Android 4.3.x, API Level 18 (Jelly Bean) | English | Portrait
    Infrastructure Failure: Internal error during validation
Nexus 7 (2012), Asus, Virtual | Android 4.3.x, API Level 18 (Jelly Bean) | English | Portrait
    Infrastructure Failure: Internal error during validation
Samsung Galaxy S3, Samsung | Android 4.3.x, API Level 18 (Jelly Bean) | English | Portrait
    Infrastructure Failure: Internal error during validation
Test running failed: No test results
Finish

Answer 1

The screenshot in Android Studio is correctly showing Infrastructure Failure: Internal error during validation. It means the test failed during validation and before sending request to Test Lab.

Usually it can be caused by incorrect app format (e.g. uploading a .aar instead of a .apk). Please check the uploaded file.