Unit testing service returns a 'cannot add service class' error message

Question

in my services folder, i have this file

abstract class AsyncUploadedFileService<T> {

    def grailsApplication
    def jesqueService

    String jobName
    String workerPool
    String _queueName

    AsyncUploadedFileService (Class<T> job, String workerPool) {
        jobName = job.simpleName
        this.workerPool = workerPool
    }
}

and I have a unit test

@Build(UploadedFile)
@TestMixin(GrailsUnitTestMixin)
@TestFor(AsyncUploadedFileService)
class AsyncUploadedFileServiceSpec extends Specification {
    def setup() {
        User.metaClass.encodePassword = {-> }
    }

    void "add to the worker pool"() {
        when:
        UploadedFile uploadedFile = UploadedFile.build()

        then:
        service.perform(uploadedFile)

    }
}

when I run my test, I get the following error

Cannot add Service class [class com.example.AsyncUploadedFileService]. It is not a Service!
org.codehaus.groovy.grails.exceptions.GrailsConfigurationException: Cannot add Service class [class com.example.AsyncUploadedFileService]. It is not a Service!
at grails.test.mixin.services.ServiceUnitTestMixin.mockService(ServiceUnitTestMixin.groovy:46)
at org.spockframework.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:138)
at org.spockframework.runtime.extension.builtin.JUnitFixtureMethodsExtension$FixtureType$FixtureMethodInterceptor.intercept(JUnitFixtureMethodsExtension.java:145)
at org.spockframework.runtime.extension.MethodInvocation.proceed(MethodInvocation.java:84)
at org.spockframework.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:138)
at org.spockframework.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:138)
at org.spockframework.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:138)

Is this error because I'm using the service.perform() syntax? If so, what other way is there of testing the AsynchUploadedFileService function?

Answer 1

You can't instantiate an abstract class, so you can't create one to test with. Make it non-abstract, or create a concrete subclass and test that.

Also, since you have a constructor with arguments, there is no default (no-arg) constructor. If you have no constructors, the compiler adds one for you (in both Java and Groovy) and in Grails since services are auto-registered, you must have a no-arg constructor (you can have others, but I can't see why you would) so Spring can create the instance. You can always manually wire up a class as a Spring bean and provide constructor args in resources.groovy, but then it wouldn't be a Grails service, so it would be better to put it in src/groovy.