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
robolectric increases the run time of tests so it's important to remove
them when they're unnecessary.
Between this change and the last one, the unit test runtime was reduced
by ~10s.
Tiger Oakes