reactor
 | core
 | console
 | custom-maven-plugin (depends on core)
 | test-deployment

public abstract class TestBase {
    private static final ResourceBundle constants = ResourceBundle.getBundle("constants");
    private static final ResourceBundle bundle = ResourceBundle.getBundle("login");
    private Connection connection;

    // ...

    Connection getConnection() {
        // Connection will be created in another method, this one just returns it.
    }
}

public class ActualTest extends TestBase {
    // Uses the connection in tests here.
}

printf "userName=$bamboo_login_userNamenpassword=$bamboo_login_password" > core/src/test/resources/login.properties

java.util.MissingResourceException: Can't find bundle for base name login, locale en_US