Dynamic Dagger Module

def preferencesStoreMock

def "setup"() {
    preferencesStoreMock = Mock(PreferencesStore)

    def module = generateModule(preferencesStoreMock) as TestModule

    DaggerInjector.start(module);
}

// generate a DaggerModule based on collection of mocks
def generateModule(Object... mocks) {

    // Very useful util class!
    def mockDetector = new MockDetector()

    // Must use DaggerModule class.
    // Using TestModule class resulted with strange looking method names
    def daggerMethods = DaggerModule.getMethods()

    mocks.collectEntries { mock ->

        // Getting only one element.
        // Dagger is based on provider's return types. By design there is one method returning
        // a type.
        def providerMethodName = daggerMethods.find {
            it.returnType == (mockDetector.isMock(mock) ?
                    mockDetector.asMock(mock).type : mock.class)
        }.getName()

        // It's very important to override the method parameters. Giving empty param list
        // just adds a new method with no arguments. Object... is an alias for any argument number.
        def providerAsClosure = { Object... objects ->
            mock
        }

        // return a map entry
        [providerMethodName, providerAsClosure]
    }
}