This is how we can apply the new test runner to remove duplication.
This commit was generated programmatically with the following commands:
```
// Replace test runners with new one.
find app/src/test -type f -exec gsed -i "s/@RunWith(RobolectricTestRunner::class)/@RunWith(FenixRobolectricTestRunner::class)/" {} +
find app/src/test -type f -exec gsed -i "s/@RunWith(AndroidJUnit4::class)/@RunWith(FenixRobolectricTestRunner::class)/" {} +
// Replace imports of old test runners with new one
find app/src/test -type f -exec gsed -i "s/org.robolectric.RobolectricTestRunner/org.mozilla.fenix.helpers.FenixRobolectricTestRunner/" {} +
find app/src/test -type f -exec gsed -i "s/androidx.test.ext.junit.runners.AndroidJUnit4/org.mozilla.fenix.helpers.FenixRobolectricTestRunner/" {} +
// Remove unused imports
find app/src/test -type f -exec gsed -i "/@Config(application = TestApplication::class)/d" {} +
find app/src/test -type f -exec gsed -i "/import org.mozilla.fenix.TestApplication/d" {} +
find app/src/test -type f -exec gsed -i "/import org.robolectric.annotation.Config/d" {} +
```
Where gsed is the GNU version of sed installed via homebrew. After
running these commands, I need to manually clean up the following files:
- FenixRobolectricTestRunner
- LocaleManagerExtensionTest
Used runBlocking to ensure we wait for the code using coroutines to execute
instead of runBlockingTest and join() since this last option led to failed
tests in CI because of
"java.lang.IllegalStateException: This job has not completed yet".