Fix for this: https://jira.grails.org/browse/GRAILS-10661

RemoteControl.groovy

package org.zirbes.grails.functional.remote

import grails.util.BuildSettingsHolder
import groovyx.remote.transport.http.HttpTransport

/**
 * Adds null safe grails specific convenient no arg constructor.
 * https://jira.grails.org/browse/GRAILS-10661
 */
class RemoteControl extends groovyx.remote.client.RemoteControl {

    static public final RECEIVER_PATH = 'grails-remote-control'

    RemoteControl() {
        super(
            new HttpTransport(
                getNullSafeFunctionalTestReceiverAddress(),
                Thread.currentThread().contextClassLoader
            ),
            Thread.currentThread().contextClassLoader
        )
    }

    private static String getNullSafeFunctionalTestReceiverAddress() {
        String base = getNullSafeFunctionalTestBaseUrl()
        if (!base) {
            throw new IllegalStateException('Cannot get receiver address for functional testing as functional test ' +
                    'base URL is not set. Are you calling this from a functional test?')
        }

        return base.endsWith('/') ? base + RECEIVER_PATH : base + '/' + RECEIVER_PATH
    }

    private static String getNullSafeFunctionalTestBaseUrl() {
        String base = BuildSettingsHolder.settings?.functionalTestBaseUrl
        if (!base || base == 'null') { base = '' }
        return base
    }

}