Grails 4.0 Mock service method in controller test

Question

I have a controller like this:

class NotificationApiController {

    def countService

    def getCount() {
        def results = countService.getCount()

        render results as JSON
    }
}

And the controller test like this:

Closure doWithSpring() {{ ->
        countService(CountService)
    }}

CountService countService

def setup() {
}

def cleanup() {
}

void "test getCount method"() {
        given:
        def countService = Mock(CountService) {
            1 * getCount(_) >> [count: 2]
        }
        when:
        def y = controller.getCount()

        then:
        y == [count: 2]
    }

It appears it always calls into the actual CountService injected in Closure doWithSpring(), not my mock countService, but without the definition of Closure doWithSpring()..., I will get this error

Cannot invoke method getCount() on null object
java.lang.NullPointerException: Cannot invoke method getCount() on null object

The documentation on unit testing in 4.0 is really limited and I am not exactly sure how should I do this. I see some samples in Grails 2.3 or 3.3. version, but they all seems not working for me, mostly due to the difference of Spock and Mixin framework I guess. Any suggestions on how to do this?

Answer 1

You have omitted some details that might affect the recommendation but the project at https://github.com/jeffbrown/chrisjiunittest shows 1 way to go about this.

https://github.com/jeffbrown/chrisjiunittest/blob/a59a58e3b6ed6b47e1a8104f3e4d3bdb138abacc/src/test/groovy/chrisjiunittest/NotificationApiControllerSpec.groovy

package chrisjiunittest

import grails.testing.web.controllers.ControllerUnitTest
import spock.lang.Specification

class NotificationApiControllerSpec extends Specification implements ControllerUnitTest<NotificationApiController> {

    void "test something"() {
        setup:
        // whether or not this is the right thing to do
        // depends on some other factors, but this is
        // an example of one approach...
        controller.countService = Mock(CountService) {
            getCount() >> [count: 2]
        }

        when:
        controller.getCount()

        then:
        response.json == [count: 2]
    }
}

Another option:

package chrisjiunittest

import grails.testing.web.controllers.ControllerUnitTest
import spock.lang.Specification

class NotificationApiControllerSpec extends Specification implements ControllerUnitTest<NotificationApiController> {

    Closure doWithSpring() {
        // whether or not this is the right thing to do
        // depends on some other factors, but this is
        // an example of one approach...
        { ->
            countService MockCountService
        }
    }

    void "test something"() {
        when:
        controller.getCount()

        then:
        response.json == [count: 2]
    }
}

class MockCountService {
    Map getCount() {
        [count: 2]
    }
}