Unit testing: testing controller using Testing Plugin

In previous posts (Unit testing: testing domain entity using Testing Plugin and Unit testing: testing service in 3 different ways (part III)) we covered how to write unit test for domain entity and for simple service using Grails Testing Plugin. In this post I would like to show You how to write a simple unit test for controller using special mock*() function and special unit test case - mockController() and ControllerUnitTestCase. Suppose that we have simple User controller. In our example we will test update_account_information method. Let's have a look in details:

class UserController {

    // Controller uses user service
    // by dynamic injection.
    def userService

    def update_account_information = {
        User user = userService.retrieveUserById(
            session.user.id)
        user.email = params.email
        user.firstName = params.firstName
        user.lastName = params.lastName

        try {
            userService.saveUser(user)

            render(view: "profile", 
                model: [user: user, 
                    accountInformationUpdateMessageCode:
                "User.account.information.updated"
                ])
        }
        catch (InvalidUserException e) {
            render(view: "profile", 
                model: [user: user])
        }
    }

    // Some other methods.

}

As You can see - nothing complicated. Let's create a simple unit test using Grails Testing Plugin:

class UserControllerTests extends ControllerUnitTestCase {

    def controller

    UserControllerTests() {
        // Will test User controller class.
        // Do not forget to call super method at first.
        // It will create test for specific controller.
        super(UserController)
    }

    void setUp() {
        // Do not forget to call super method at first.
        super.setUp()
          
        // You have to initialize controller manually,
        // There is no dynamic injection.
        controller = new UserController()

        // Initialise the user service.
        def userService = new UserService()
     
        controller.userService = userService
    }

    void testUpdateAccountInformationSuccess() {
        // Mocking domain classes.
        def user = new User(id: 1L, 
            email: "taras.matyashovsky@gmail.com", 
            firstName: "Taras", lastName: "Matyashovsky", 
            password: "some hash")
        mockDomain(User, [user])

        // Putting user into session.
        controller.session.user = user

        // Setting controller's parameters.
        controller.params.email = 
            "taras.matyashovsky@gmail.com"
        controller.params.firstName = "Tarasuk"
        controller.params.lastName = "Matyash"

        // Testing the target method.
        controller.update_account_information()

        // Assertions.
        assertEquals "profile", renderArgs.view
        assertEquals user, renderArgs.model.user
        assertEquals "User.account.information.updated",
renderArgs.model.accountInformationUpdateMessageCode
    }

    void testUpdateAccountInformationFailure() {
        // Mocking domain classes.
        def user = new User(id: 1L, 
            email: "taras.matyashovsky@gmail.com", 
            firstName: "Taras", 
           lastName: "Matyashovsky")
        mockDomain(User, [user])

        // Putting user into session.
        controller.session.user = user

        // Passing invalid parameters.
        controller.params.email = "INVALID EMAIL ADDRESS"
        controller.params.firstName = "Tarasuk"
        controller.params.lastName = "Matyash"

        // Testing the target method.
        controller.update_account_information()

        assertEquals "profile", renderArgs.view
        assertEquals user, renderArgs.model.user
    }

}

Pay attention to few key points:

• by using ControllerUnitTestCase the controller's render method and params property work without any work on our part. This is true of all the dynamic properties and methods of the controller: request, response, params, session, controllerName, redirect, etc. All stuff is done by Testing Plugin
• do not forget to call super methods - this will make sure that test will mock appropriate controller class

That's all for now.