Grails - Spock Unit Test can't find test

My Spock Test in Grails errors out saying "No tests found". I'm following the a guide here: http://guides.grails.org/creating-your-first-grails-app/guide/index.html 9 Testing your App

ValueEstimateServiceSpec.groovy is located at: grails-apps\myApp\src\test\groovy\org\grails\myapp

What am I doing wrong? Thanks!

$ ./grailsw test-app org.grails.myapp.ValueEstimateServiceSpec
:compileJava NO-SOURCE
:compileGroovy UP-TO-DATE
:buildProperties
:processResources UP-TO-DATE
:classes UP-TO-DATE
:compileTestJava NO-SOURCE
:compileTestGroovy
:processTestResources NO-SOURCE
:testClasses
:test
:compileIntegrationTestJava NO-SOURCE
:compileIntegrationTestGroovy
:processIntegrationTestResources UP-TO-DATE
:integrationTestClasses
:integrationTest FAILED
:mergeTestReports

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':integrationTest'.
> No tests found for given includes: [org.grails.myapp.ValueEstimateServiceSpec]

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 9.77 secs
Tests FAILED |
Test execution failed

Here is my code for the test class

package org.grails.myapp

import grails.testing.gorm.DataTest
import grails.testing.services.ServiceUnitTest
import spock.lang.Specification

class ValueEstimateServiceSpec extends Specification implements ServiceUnitTest<ValueEstimateService>, DataTest {

    void setupSpec() {
        mockDomain Make
        mockDomain Model
        mockDomain Vehicle
    }

    void testEstimateRetrieval() {
        given: 'a vehicle'
        def make = new Make(name: 'Test')
        def model = new Model(name: 'Test', make: make)
        def vehicle = new Vehicle(year: 2000, make: make, model: model, name: 'Test vehicle')

        when: 'service is called'
        def estimate = service.getEstimate(vehicle)

        then: 'a non-zero result is returned'
        estimate > 0

        and: 'estimate is not too large'
        estimate < 1000000
    }
}