Some locale related tests are only supposed to run under a specific locale, e.g., test comparing an error output would eliminate the boilerplate code such as:
```
Locale orig = Locale.getDefault();
try {
    Locale.setDefault(Locale.US);
    // test code
} finally {
    Locale.setDefault(orig);
}
```

by introducing
```
@requires user.language=en && user.country=US
```
option.