How to mock/stub a collaborator's getter and make it return a stub

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1

Hello,

I’m writing a test with Gradle and wonder how to stub an interface that is a collaborator’s collaborator (from my class under test (CUT) point-of-view).

project.logger would return an instance of the interface org.gradle.api.Project.Logger, and logger is the getter I’d need to mock.

Any ideas how to create a Logger without implementing the Logger interface and make my cut instance return it?
I guess I’m missing something as I’m quite new to mock testing.

Thanks
Jan

The TestCase:

import org.gradle.api.Project

class MyClassUnderTestTestCase{
    @Test
    void testDoSomething(){
        StubFor projectStub = new StubFor(Project)
        projectStub.demand.getLogger { } // create a Logger stub here?
        
        projectStub.use {
            def project = { } as Project
            MyClassUnderTest cut = new MyClassUnderTest(project)
            cut.doSomething()
            //Further assertions
        }
        projectStub.expect.verify()
    }
}

My CUT:

import org.gradle.api.Project

class MyClassUnderTest{
    private Project project
    
    MyClassUnderTest(Project project){
        this.project = project
    }

    void doSomething(){
        project.logger.info "Start doing something..."    // project.logger should now return a stubbed instance of Logger
        //Do some stuff
    }
}