Since you have selected "Use APK Expansion setting", you can not test the package/application locally (copying .apk to your mobile device and then test).
Kindly follow below steps to test your package from Google Play Developer Console:
You can test your expansion files using the Alpha distribution channel on your Developer Console.
APK expansion files can’t be tested with Draft APKs. To properly test APK expansion files, your APK must be published to Alpha, Beta, or Production google play.
Note: Kindly package the project by selecting "Use APK Expansion setting" & "Google Play".
1.Go to your Google Play Developer Console.
2.Select your app.
3.On the left menu, click APK.
4.Using the Alpha testing tab, upload an Alpha version of your APK without adding your expansion files.
5.Click Save and Publish.
6.Upload a new Alpha version of your APK and attach the expansion files.