In the past i always stumbled across a certain problem with phpspec:
Lets assume i have a method which calls multiple methods on another object
class Caller {
public function call(){
$this->receiver->method1();
...
$this->receiver->method2();
}
}
In BDD i would first write a test which makes sure method1 will be called.
function it_calls_method1_of_receiver(Receiver $receiver){
$receiver->method1()->shouldBeCalled();
$this->call();
}
And then i would write the next test to assure method2 will be called.
function it_calls_method2_of_receiver(Receiver $receiver){
$receiver->method2()->shouldBeCalled();
$this->call();
}
But this test fails in phpspec because method1 gets called before method2.
To satisfy phpspec i have to check for both method calls.
function it_calls_method2_of_receiver(Receiver $receiver){
$receiver->method1()->shouldBeCalled();
$receiver->method2()->shouldBeCalled();
$this->call();
}
My problem with that is, that it bloats up every test. In this example it's just one extra line but imagine a method which builds an object with a lot of setters.
I would need to write all setters for every test. It would get quite hard to see the purpose of the test since every test is big and looks the same.
I'm quite sure this is not a problem with phpspec or bdd but rather a problem with my architecture. What would be a better (more testable) way to write this?
For example:
public function handleRequest($request, $endpoint){
$endpoint->setRequest($request);
$endpoint->validate();
$endpoint->handle();
}
Here i validate if an request provides all necessary info for a specific endpoint (or throw an exception) and then handle the request. I choose this pattern to separate validating from the endpoint logic.
Prophecy, the mocking framework used by PhpSpec, is very opinionated. It follows the mockist approach (London School of TDD) which defends that we should describe one behaviour at a time.
A mock is a test, so you want to keep one mock per test. You can mock all the calls, but that will not look elegant. The recommended approach is to separate the behaviour you are testing and select the mock you need for that behaviour, stubbing the rest of the calls. If you see yourself creating loads of stubs in one test that indicates feature envy — you should consider moving the behaviour to the callee, or add a man in the middle.
Say you decide to go ahead and describe the code you have, without refactoring. If you are interested in the second call, as per your example, you should stub the other calls using willReturn, or similar. E.g. $endpoint->setRequest(Argument::type(Request::class))->willReturn() instead of shouldBeCalled().
Related
I created a simple test for my new Laravel 7 application. But when I run php artisan test I get the following error.
Target [Illuminate\Contracts\View\Factory] is not instantiable.
The error doesn't appear when I go to the page in the browser.
$controller = new HomeController();
$request = Request::create('/', 'GET');
$response = $controller->home($request);
$this->assertEquals(200, $response->getStatusCode());
Although "Just write feature tests" may seem like a cop-out ("They're not unit tests!"), it is sound advice if you do not want to get bogged down by framework-specific knowledge.
You see, this is one of those problems that come from using facades, globals, or static methods. All sorts of things happen outside of your code (and thus your test code) in order for things to work.
The problem
To understand what is going on, you first need to know how Laravel utilizes Containers and Factories in order to glue things together.
Next, what happens is:
Your code (in HomeController::home() calls view() somewhere.
view() calls app() to get the factory that creates Views1
app() calls Container::make
Container::make calls Container::resolve1
Container::resolve decides the Factory needs to be built and calls Container::build to do so
Finally Container::build (using PHP's ReflectionClass figures out that \Illuminate\Contracts\View\Factory can not be Instantiated (as it is an interface) and triggers the error you see.
Or, if you're more of a visual thinker:
The reason that the error is triggered is that the framework expects the container to be configured so that a concrete class is known for abstracts (such as interfaces).
The solution
So now we know what is going on, and we want to create a unit-test, what can we do?
One solution might seem to not use view. Just inject the View class yourself! But if you try to do this, you'll quickly find yourself going down a path that will lead to basically recreating loads of framework code in userland. So not such a good idea.
A better solution would be to mock view() (Now it is really a unit!). But that will still require recreating framework code, only, within the test code. Still not that good.[3]
The easiest thing is to simply configure the Container and tell it which class to use. At this point, you could even mock the View class!
Now, purists might complain that this is not "unit" enough, as your tests will still be calling "real" code outside of the code-under-test, but I disagree...
You are using a framework, so use the framework! If your code uses glue provided by the framework, it makes sense for the test to mirror this behavior. As long as you don't call non-glue code, you'll be fine![4]
So, finally, to give you an idea of how this can be done, an example!
The example
Lets say you have a controller that looks a bit like this:
namespace App\Http\Controllers;
class HomeController extends \Illuminate\Routing\Controller
{
public function home()
{
/* ... */
return view('my.view');
}
}
Then your test[5] might look thus:
namespace Tests\Unit\app\Http\Controllers;
use App\Http\Controllers\HomeController;
use Illuminate\Contracts\View\Factory;
class HomeControllerTest extends \PHPUnit\Framework\TestCase
{
public function testHome()
{
/*/ Arange /*/
$mockFactory = $this->createMock(Factory::class);
app()->instance(Factory::class, $mockFactory);
/*/ Assert /*/
$mockFactory->expects(self::once())
->method('make')
->with('my.view')
;
/*/ Act /*/
(new HomeController())->home();
}
}
A more complex example would be to also create a mock View and have that be returned by the mock factory, but I'll leave that as an exercise to the reader.
Footnotes
app() is asked for the interface Illuminate\Contracts\View\Factory, it is not passed a concrete class name
The reason Container::make does nothing other than call another function is that the method name make is defined by PSR-11 and the Laravel container is PSR compliant.
Also, the Feature test logic provided by Laravel already does all of this for you...
Just don't forget to annotate the test with #uses for the glue that is needed, to avoid warnings when PHPUnit is set to strict mode regarding "risky" tests.
Using a variation of the "Arrange, Act, Assert" pattern
This is not how you test endpoints in Laravel. You should let Laravel instantiate the application as it is already setup in the project, the examples you can see here.
What you already wrote can be rewritten to something like this.
$response = $this->call('GET', route('home')); // insert the correct route
$response->assertOk(); // should be 200
For the test to work, you should extend the TestCase.php, that is located in your test folder.
If you're finding this in The Future and you see #Pothcera's wall of text, here's what you need to know:
The ONLY reason he's doing any of that and the ONLY reason you're seeing this in the first place in a Unit test is because he and you haven't changed from PHPUnit\Framework\TestCase to Tests\TestCase in the test file. This exception doesn't exist when you extend the test case that includes app().
My advice would be to simply extend the correct base test case and move on with your life.
Given this code:
function testMe($a)
{
if ($a)
{
return 1;
}
else
{
return $this->testMe(true);
}
}
testMe() cannot be mocked, because then I cant call it. On the other hand, it must be mocked…
I'd say your question has some philosophical potential. I'll try to answer it the way you ask it but before, allow me to comment on your comprehension:
testMe() cannot be mocked, because then I cant call it. On the other hand, it must be mocked… [italics by me]
The unfinished sentence is wrong. You probably sensed it already because you didn't finish it. In a unit test you don't mock the unit. So you put the unit under test, and the unit is the method. That is the smallest part (unit) that can be tested.
What perhaps actually creates a bit of confusion is the recursion within the method.
So you actually ask how to unit-test recursion or a single method call within that recursion. But do you really need to test it?
I would say no. And that is because the recursion is an implementation detail of the method. From the outside it should not make any difference if you exchange the internal algorithm from recursion to a stack based loop for example.
But despite the fact I say you don't need that (and I hope you already have understood the argumentation I outlined), it technically is possible for your very specific scenario to test such a method-call without re-writing the code under test by re-binding $this. Then you can replace the subject under test ($this) with a mock when called. So that you have two methods: The one to test and the mocked one that is accessible via $this->testMe().
This could be done by instantiating the subject under test, create a mock, use PHP's reflection to obtain the closure of testMe() then re-bind $this on the closure to the mock and then call the closure for your test assertions.
I would not call this a unit-test any longer because as I outlined earlier, you're testing internals / privates, so you can use it more to actually test fragments of the recursion under certain circumstances and other similar detailed things that will more actually proof / debug fragments of code. You normally only need that under very specific circumstances when code is really high valuable.
Don't use your little confusion about the recursion to think this is an entirely important place to test on it's own. But if you want to get your fingers dirty, it's perhaps something worth to play with to learn about PHP reflection, closures and re-binding $this.
I am quite new to OOP, so this is really a basic OOP question, in the context of a Laravel Controller.
I'm attempting to create a notification system system that creates Notification objects when certain other objects are created, edited, deleted, etc. So, for example, if a User is edited, then I want to generate a Notification regarding this edit. Following this example, I've created UserObserver that calls NotificationController::store() when a User is saved.
class UserObserver extends BaseObserver
{
public function saved($user)
{
$data = [
// omitted from example
];
NotificationController::store($data);
}
}
In order to make this work, I had to make NotificationController::store() static.
class NotificationController extends \BaseController {
public static function store($data)
{
// validation omitted from example
$notification = Notification::create($data);
}
I'm only vaguely familiar with what static means, so there's more than likely something inherently wrong with what I'm doing here, but this seems to get the job done, more or less. However, everything that I've read indicates that static functions are generally bad practice. Is what I'm doing here "wrong," per say? How could I do this better?
I will have several other Observer classes that will need to call this same NotificationController::store(), and I want NotificationController::store() to handle any validation of $data.
I am just starting to learn about unit testing. Would what I've done here make anything difficult with regard to testing?
I've written about statics extensively here: How Not To Kill Your Testability Using Statics. The gist of it as applies to your case is as follows:
Static function calls couple code. It is not possible to substitute static function calls with anything else or to skip those calls, for whatever reason. NotificationController::store() is essentially in the same class of things as substr(). Now, you probably wouldn't want to substitute a call to substr by anything else; but there are a ton of reasons why you may want to substitute NotificationController, now or later.
Unit testing is just one very obvious use case where substitution is very desirable. If you want to test the UserObserver::saved function just by itself, because it contains a complex algorithm which you need to test with all possible inputs to ensure it's working correctly, you cannot decouple that algorithm from the call to NotificationController::store(). And that function in turn probably calls some Model::save() method, which in turn wants to talk to a database. You'd need to set up this whole environment which all this other unrelated code requires (and which may or may not contain bugs of its own), that it essentially is impossible to simply test this one function by itself.
If your code looked more like this:
class UserObserver extends BaseObserver
{
public function saved($user)
{
$data = [
// omitted from example
];
$this->NotificationController->store($data);
}
}
Well, $this->NotificationController is obviously a variable which can be substituted at some point. Most typically this object would be injected at the time you instantiate the class:
new UserObserver($notificationController)
You could simply inject a mock object which allows any methods to be called, but which simply does nothing. Then you could test UserObserver::saved() in isolation and ensure it's actually bug free.
In general, using dependency injected code makes your application more flexible and allows you to take it apart. This is necessary for unit testing, but will also come in handy later in scenarios you can't even imagine right now, but will be stumped by half a year from now as you need to restructure and refactor your application for some new feature you want to implement.
Caveat: I have never written a single line of Laravel code, but as I understand it, it does support some form of dependency injection. If that's actually really the case, you should definitely use that capability. Otherwise be very aware of what parts of your code you're coupling to what other parts and how this will impact your ability to take it apart and refactor later.
How do you write a unit test for a method that calls other methods of the same class, but doesn't return a value? (Let's say with PHPUnit.)
For example, let's say that I have the following class:
class MyClass {
public function doEverything() {
$this->doA();
$this->doB();
$this->doC();
}
public function doA() {
// do something, return nothing
}
public function doB() {
// do something, return nothing
}
public function doC() {
// do something, return nothing
}
}
How would you test doEverything()?
EDIT:
I'm asking this because from what I've read it seems like pretty much every method should have its own dedicated unit test. Of course, you also have functional and integration tests, but those target specific routines, so to speak (not on a per method level necessarily).
But if pretty much every method needs its own unit test, I'm thinking it would be "best practice" to unit test all of the above methods. Yes/no?
Okay! I've figured it out! As might be expected, mocking is what I need in this situation--and mocking a sibling method is called partial mocking. There's some pretty great info about PHPUnit mocking in this article by Juan Treminio.
So to test doEverything() in the above class, I would need to do something like this:
public function testDoEverything()
{
// Any methods not specified in setMethods will execute perfectly normally,
// and any methods that ARE specified return null (or whatever you specify)
$mock = $this->getMockBuilder('\MyClass')
->setMethods(array('doA', 'doB', 'doC'))
->getMock();
// doA() should be called once
$mock->expects($this->once())
->method('doA');
// doB() should be called once
$mock->expects($this->once())
->method('doB');
// doC() should be called once
$mock->expects($this->once())
->method('doC');
// Call doEverything and see if it calls the functions like our
// above written expectations specify
$mock->doEverything();
}
That's it! Pretty easy!
BONUS: If you use Laravel and Codeception...
I'm using the Laravel Framework as well as Codeception, which made it a little bit trickier to figure out. If you use Laravel and Codeception you'll need to do a little bit more to get it working, since the Laravel autoloading doesn't by default connect into the PHPUnit tests. You'll basically need to update your unit.suite.yml to include Laravel4, as shown below:
# Codeception Test Suite Configuration
# suite for unit (internal) tests.
class_name: UnitTester
modules:
enabled: [Asserts, UnitHelper, Laravel4]
Once you've updated your file, don't forget to call php codecept.phar build to update your configuration.
While your mocking test does achieve your goal, I would argue that you've decreased confidence in the code. Compare the original trivial method to the complicated method that tests it. The only way the method under test can fail is by forgetting to add one of the method calls or mistype a name. But you're now doubly-likely to do that with all that additional code, and it doesn't have any tests!
Rule: If your test code is more complicated than the code under test, it needs its own tests.
Given the above, you're better off finding another way to test the original code. For the method as written--three method calls with no parameters--inspection by eyeball is sufficient. But I suspect that the method does have some side-effects somewhere, otherwise you could delete it.
Unit testing is about testing the class as a unit, not each method individually. Testing each method alone is a good indication that you're writing your tests after the code. Employing Test Driven Development and writing your tests first will help you design a better class that is more-easily testable.
Reading up and picking up on unit testing, trying to make sense of the following post on that explains the hardships of static function calls.
I don't clearly understand this issue. I have always assumed static functions were a nice way of rounding up utility functions in a class. For example, I often use static functions calls to initialise, ie:
Init::loadConfig('settings.php');
Init::setErrorHandler(APP_MODE);
Init::loggingMode(APP_MODE);
// start loading app related objects ..
$app = new App();
// After reading the post, I now aim for this instead ...
$init = new Init();
$init->loadConfig('settings.php');
$init->loggingMode(APP_MODE);
// etc ...
But, the few dozen tests I had written for this class are the same. I changed nothing and they still all pass. Am I doing something wrong?
The author of the post states the following:
The basic issue with static methods is they are procedural code. I have no idea how to unit-test procedural code. Unit-testing assumes that I can instantiate a piece of my application in isolation. During the instantiation I wire the dependencies with mocks/friendlies which replace the real dependencies. With procedural programing there is nothing to “wire” since there are no objects, the code and data are separate.
Now, I understand from the post that static methods create dependencies, but don't grasp intuitively why one cannot test the return value of a static method just as easily as a regular method?
I will be avoiding static methods, but I would of liked having an idea of WHEN static methods are useful, if at all. It seems from this post static methods are just about as evil as global variables and should be avoided as much as possible.
Any additional information or links on the subject would be greatly appreciated.
Static methods themselves aren't harder to test than instance methods. The trouble arises when a method--static or otherwise--calls other static methods because you cannot isolate the method being tested. Here is a typical example method that can be difficult to test:
public function findUser($id) {
Assert::validIdentifier($id);
Log::debug("Looking for user $id"); // writes to a file
Database::connect(); // needs user, password, database info and a database
return Database::query(...); // needs a user table with data
}
What might you want to test with this method?
Passing anything other than a positive integer throws InvalidIdentifierException.
Database::query() receives the correct identifier.
A matching User is returned when found, null when not.
These requirements are simple, but you must also setup logging, connect to a database, load it with data, etc. The Database class should be solely responsible for testing that it can connect and query. The Log class should do the same for logging. findUser() should not have to deal with any of this, but it must because it depends on them.
If instead the method above made calls to instance methods on Database and Log instances, the test could pass in mock objects with scripted return values specific to the test at hand.
function testFindUserReturnsNullWhenNotFound() {
$log = $this->getMock('Log'); // ignore all logging calls
$database = $this->getMock('Database', array('connect', 'query');
$database->expects($this->once())->method('connect');
$database->expects($this->once())->method('query')
->with('<query string>', 5)
->will($this->returnValue(null));
$dao = new UserDao($log, $database);
self::assertNull($dao->findUser(5));
}
The above test will fail if findUser() neglects to call connect(), passes the wrong value for $id (5 above), or returns anything other than null. The beauty is that no database is involved, making the test quick and robust, meaning it won't fail for reasons unrelated to the test like network failure or bad sample data. It allows you to focus on what really matters: the functionality contained within findUser().
Sebastian Bergmann agrees with Misko Hevery and quotes him frequently:
Stubbing and Mocking Static Methods
Unit-Testing needs seams, seams is where we prevent the execution of normal code path and is how we achieve isolation of the class under test. Seams work through polymorphism, we override/implement class/interface and then wire the class under test differently in order to take control of the execution flow. With static methods there is nothing to override. Yes, static methods are easy to call, but if the static method calls another static method there is no way to override the called method dependency.
The main issue with static methods is that they introduce coupling, usually by hardcoding the dependency into your consuming code, making it difficult to replace them with stubs or mocks in your Unit-Tests. This violates the Open/Closed Principle and the Dependency Inversion Principle, two of the SOLID principles.
You are absolutely right that statics are considered harmful. Avoid them.
Check the links for additional information please.
Update: note that while statics are still considered harmful, the capability to stub and mock static methods has been removed as of PHPUnit 4.0
I do not see any problem when testing static methods (at least none that doesn't exists in non-static methods).
Mock objects are passed to classes under test using dependency injection.
Mock static methods can be passed to classes under test using a suitable autoloader or manipulating the include_path.
Late static binding deals with methods calling static methods in the same class.