How to test a method that starts my application? - unit-testing

I have a command line application written in a scripting language. The startup script does something like this:
import 'App'
app = new App()
app.run()
The run()method is responsible for instantiating all required objects and then actually starting the application:
import 'Artist', 'Song', 'Listener'
class App
method run()
artist = new Artist()
song = new Song()
listener = new Listener(artist, song)
listener->listen()
end
end
How can I write a test to make sure that run() is doing what it's supposed to do?
My initial thought was to add an optional argument so that I could pass a mock of Listener and expect listen() to be called, but it does not tell me if the actual Listener class will be instantiated correctly when running the application.
Another idea is to pass all the objects to run(), but then I would have to create them on the startup script, which I'd also have to test and the same problem arises.

I would say don't test that objects are created correctly. I presume you test the constructor for the Listener class in its own unit tests. Given that I would say you can trust the interpreter to construct your object correctly. If you want to test that the interpreter can construct classes then you're testing your scripting language not your app.
If you want to functionally test the App class that would mean checking that listen() has done whatever it is supposed to do. How you do that would in turn depend on what listen() is supposed to do.
The other option is to expose what you need to test, of course there are lots of arguments about changing your code to make it more testable. I won't go into them here. But you could expose you Listener class in the App so you could query it in testing.
[Slight aside: some languages provide the means to expose properties to specific assemblies so that you don't have to expose properties publicly (internalsvisibleto, I'm looking at you c#).]

Related

how to mock a service so as to inject it properly

I'm trying to mock a service within a functional test, which is used by another service:
$client = static::createClient();
$stub = $this->createMock(MailService::class);
$stub->method('sendMailToUser')->willReturn(9);
$client->getContainer()->set('belka.auth_bundle.mail_service', $stub);
// the *real* test should start here
if I try to put a die command inside the original sendMailToUser, what I get is the code stop running, although I tried to mock it by returning 9. What's wrong with it? The service I'm testing has the following declaration, then I guessed the injected service was the one wrote above:
belka.auth_bundle.user_handler:
class: Belka\AuthBundle\Handler\UserHandler
arguments:
- '#belka.auth_bundle.user_repository'
- '#belka.auth_bundle.mail_service'
calls:
- [setRequest, ["#request_stack"]]
- [setSettings, ["#belka.auth_bundle.setting_handler"]]
- [setBodyJsonHandler, ["#belka.container_support_bundle.body_json_handler"]]
- [setQuantityHandler, ["#belka.container_support_bundle.quantityhandler"]]
I trust Symfony to create services correctly, and so I won't usually get services to then test within them (I do have a smoke-test that tries to create almost every service though).
So, if you are trying to get a 'belka.auth_bundle.user_handler', I would manually create the Belka\AuthBundle\Handler\UserHandler instance, with your mock as one of the arguments.
For services that are required deeper within the services, there aren't easy ways to mock them (or to get the mock into place), but you can use the service container environments to override them.
For example, I have a service that tests if a Request has come from a bot - but while running functional tests I replace it entirely with a service that always says 'not a bot', by overriding my 'app.bot_detect.detector' service in /config/services_test.yml
# set the default bot detector to a simple fake, always return false
app.bot_detect.detector:
class: App\Services\BotDetectorNeverBot
In the main config/services.yml, the class would really perform the check, but the method in the test environment's BotDetectorNeverBot class always says false.
In the same way, you could override belka.auth_bundle.mail_service in services_test.yml (or config_test.yml) to not send email, and store something instead. You just have to make sure you are including '*_test.yml' files appropriately.

How to unit test Service Fabric Actor with State

I've started writing unit tests for new actor with state. The state is initialised in the OnActivateAsync method which is called by Service Fabric when the Actor is activated.
When unit testing, I'm creating the Actor myself and as the method is protected I don't have access from my unit test to call this method myself.
I'm wondering on the usual approach for this kind of testing. I could mock the Actor and mock the state, but for the code I want to test call the original. Am wondering if there is another approach I've not come across.
Another approach would be to move the State initialisation to somewhere else like a public method or in the constructor but the template for an Actor has the code there so it may be a best practice.
Use the latest version of ServiceFabric.Mocks NuGet package. It contains special extension to invoke OnActivateAsync protected method and the whole tool set for ServiceFabric unit testing.
var svc = MockActorServiceFactory.CreateActorServiceForActor<MyActor>();
var actor = svc.Activate(new ActorId(Guid.NewGuid()));
actor.InvokeOnActivateAsync().Wait();
I like to use the InternalsVisibleTo attribute and an internal method on the actor, which calls the OnActivateAsync method.
In the target Actor project, AssemblyInfo.cs add a line like this:
[assembly: InternalsVisibleTo("MyActor.Test")]
Where "MyActor.Test" is the name of the test project you want to grant access to your internal members.
In the target Actor class add a method something like this:
internal Task InvokeOnActivateAsync()
{
return OnActivateAsync();
}
This way you can invoke the OnActivateAsync method from your test project something like this:
var actor = CreateNewActor(id);
actor.InvokeOnActivateAsync()
I appreciate this is not ideal, but you can use reflection to call the OnActivateAsync() method.
For example,
var method = typeof(ActorBase).GetMethod("OnActivateAsync", BindingFlags.Instance | BindingFlags.NonPublic);
await (Task)method.Invoke(actor, null);
This way you'll be testing the actual method you want to test and also won't be exposing methods you don't really want to expose.
You may find it useful to group the creation of the actor and the manual call to OnActivateAsync() in a single method so that it's used across your test suite and it mimics the original Service Fabric behaviour.

Symfony2: Mocked service is set in the container but not used by the controller (it still uses the original service)

I'm writing the functional tests for a controller.
It uses a class to import some data from third party websites and to do this I wrote a class that I use into Symfony setting it a service.
Now, in my functional tests, I want to substitute this service with a mocked one, set it in the container and use it in my functional tests.
So my code is the following:
// Mock the ImportDataManager and substitute it in the services container
$mockDataImportManager = $this->getMockBuilder('\AppBundle\Manager\DataImportManager')->disableOriginalConstructor()->getMock();
$client->getContainer()->set('shq.manager.DataImport', $mockDataImportManager);
$client->submit($form);
$crawler = $client->followRedirect();
As I know that between each request the client reboots the kernel and I have to set again the mocked class, I set the mock immediately before the calling to $client->submit.
But this approach seems not working for me and the controller still continue to use the real version of the service instead of the mocked one.
How can I use the mocked class to avoid to call the remote website during my functional test?
If I dump the set mocked service, I can see it is correctly set:
dump($client->getContainer()->get('shq.manager.DataImport'));die;
returns
.SetUpControllerTest.php on line 145:
Mock_DataImportManager_d2bab1e7 {#4807
-__phpunit_invocationMocker: null
-__phpunit_originalObject: null
-em: null
-remotes: null
-tokenGenerator: null
-passwordEncoder: null
-userManager: null
}
But it is not used during the $form->submit($form) call and, instead, is used the original service.
UPDATE
Continuing searching for a solution, I landed on this GitHub page from the Symfony project, where a user asks for a solution to my same problem.
The second call doesn't use the mocked/substituted version of his class, but, instead, the original one.
Is this the correct behavior? So, is it true that I cannot modify the service container on a second call to the client?
Yet, I don't understand why the service is not substituted in the container and I haven't a real solution to that problem.
Anyway I found some sort of workaround, in reality more correct as solution (also if it remains unclear why the service is not substituted and this is a curiosity I'd like to solve - maybe because the $client->submit() method uses the POST method?).
My workaround is a simple test double.
I create a new class in AppBundle/Tests/TestDouble and called it DataImportManagerTestDouble.php.
It contains the unique method used by the controller:
namespace AppBundle\Tests\TestDouble;
use AppBundle\Entity\User;
class DataImportManagerTestDouble
{
public function importData(User $user)
{
return true;
}
}
Then, I instantiate it in the config_test.yml (app/config/config_test.yml) file in the following way:
services:
shq.manager.DataImport:
class: AppBundle\Tests\TestDouble\DataImportManagerTestDouble
This way, during the tests, and only during the tests, the class loaded as service is the TestDouble and not the original one.
So the test pass and I'm (relatively) happy. For the moment, at least.

How do I get Spring app context into my test classes without cut-copy-paste?

I want to initialize Spring once and only once in my application/running code (and I do that in the main(String[] args method).
Now I am writing tests, I also want to init only once in my unit test code (but it should already be init'd for my application to run. How do I structure my code/classs so that I would not have to cut-copy-paste code from my app code into my test code and reuse the same Spring context that is init'd in main()?
In other words, I would have to be init'd in the application code and then somehow passed to my unit or system test code so that it has the same instance of 'context' throughout.
I am initializing the Spring context in a
public static void main(String[] args) {
...
ApplicationContext context =
new AnnotationConfigApplicationContext(SpringConfig.class);
...
}
Thanks
J.V.
You could set up a #Rule. Use a singleton instance across all your tests. Have the rule maintain state and on first invocation set up the Spring context. All other tests would just use the existing context. Expose the context via a getter so that tests can use the context to retrieve beans.
In response to your comment... First here is a link to check out:
Rules Wiki - Custom Rules
Normally when you use a Rule you create the Rule instance for each class. In this case you would want to use a singleton so implement your Rule as a singleton class with a static getInstance method that the tests would use to share the single instance.
If you use the same instance (singleton) for all the tests and have it hole as a field the Spring context, you have state.
Have the Rule create and start the Spring context and have a getter that returns the context so that your tests can have access to the context.
The getter goes in the Rule.

Mocking an object with Moq, using Ninject when doing UnitTesting

I'm having trouble using Moq in a UnitTesting project with Ninject.
First a few lines about my solution. It contains several projects (BussinesLogic, DAL, Infrastructure...). My goal is to UnitTest the logic i'm using in BussinessLogic project.
The solution is basicly for a windows service, but i've put in the logic so it can be run standalone. I'm using Ninject and i specify weather i want to use the ProductionModule or the TestingModule (windows service uses ProductionModule, console app uses TestingModule)
I'm using a factory pattern to get ninject kernel whenever i need it inside my application.
My TestingModule inherits from NinjectModule where i override the Load() method and there i do the binding. For instance:
Bind<IStorageManager>().To<StubStorageManager>();
I have the StubStorageManager but it's empty. It contains just the declaration of methods from IStorageManager.
The thing i would like to do is (in laymans terms):
Create a unitTest where i would create a new kernel specifying the TestingModule as it's parameter. Then i would like to create a mock object (let's say a mock of IStorageManager) storageManagerMock. Some method in IStorageManager returns a messageObject so i would probably need to mock that too, couse the bussiness logic is doing something based on that messageObject. So i would like to somehow set properties to that message object and then call some businessLogic method on it, so i can see if the logic works correctly.
I hope i didn't complicate it too much.
Please bear with me, i'm completely new to mocking and dependency injection, but am willing to learn.
I doubt you really want to be using Ninject in your tests. The whole point of using ninject is that you can decouple everything. You also want to try and keep everything decoupled from the dependency container itself if possible. Pass it in if you have to, or pass in factories that create the required object and have the container pass in the factory.
I suspect you probably want to do something like this:
public void ATest(){
//create a mock StorageManager
var managerMock = new Mock<IStorageManager>();
//create a mock MessageObject to be used by business logic
var messageObjectMock = new Mock<MessageObject>();
//have the storage manager return the mock message when required
managerMock.Setup(x => x.GetMessageObject()).Returns(messageObjectMock.Object);
//set up message expectations
messageObjectMock.Setup(x => x.ThisValueExpected).Returns(10);
messageObjectMock.Setup(x => x.ThisFunctionShouldBeCalled()).Verifiable("Function not called.");
//thing to test
BusinessLogicObject blo = new BusinessLogicObject(managerMock.Object);
blo.DoTheThingImTesting();
//make sure the business logic called the expected function, or do whatever check you need...
messageObjectMock.Verify();
}