How can I do a partial integration test (phpunit)? - php

Question

I am working on an extension (app) of nextcloud (which is based on Symfony). I have a helper class to extract data from the request that is passed by the HTTP server to PHP. A much-reduced one could be something like this (to get the point here):
<?php
namespace OCA\Cookbook\Helpers;
class RequestHelper {
public function getJson(){
if($_SERVER['Request_Method' === 'PUT'){ // Notice the typos, should be REQUEST_METHOD
$raw = file_get_content('php://input');
return json_decode($raw, true);
} else { /* ... */ }
}
}
Now I want to test this code. Of course, I can do some unit testing and mock the $_SERVER variable. Potentially I would have to extarct the file_get_content into its own method and do a partial mock of that class. I get that. The question is: How much is this test worth?
If I just mimick the behavior of that class (white box testing) in my test cases I might even copy and paste the typo I intentionally included here. As this code is an MWE, real code might get more complex and should be compatible with different HTTP servers (like apache, nginx, lighttpd etc).
So, ideally, I would like to do some automated testing in my CI process that uses a real HTTP server with different versions/programs to see if the integration is working correctly. Welcome to integration testing.
I could now run the nextcloud server with my extension included in a test environment and test some real API endpoints. This is more like functional testing as everything is tested (server, NC core, my code and the DB):
phpunit <---> HTTP server <---> nextcloud core <---> extension code <---> DB
^
|
+--> RequestHelper
Apart from speed, I have to carefully take into account to test all possible paths through the class RequestHelper (device under test, DUT). This seems a bit brittle to me in the long run.
All I could think of is adding a simple endpoint only for testing the functionality of the DUT, something like a pure echo endpoint or so. For the production use, I do not feel comfortable having something like this laying around.
I am therefore looking for an integration test with a partial mock of the app (mocking the business logic + DB) to test the route between the HTTP server and my DUT. In other words, I want to test the integration of the HTTP server, nextcloud core, my controller, and the DUT above without any business logic of my app.
How can I realize such test cases?
Edit 1
As I found from the comments the problem statement was not so obviously clear, I try to explain a bit at the cost of the simplicity of the use-case.
There is the nextcloud core that can be seen as a framework from the perspective of the app. So, there can be controller classes that can be used as targets for URL/API endpoints. So for example /apps/cookbook/recipe/15 with a GET method will fetch the recipe with id 15. Similarly, with PUT there can be a JSON uploaded to update that recipe.
So, inside the corresponding controller the structure is like
class RecipeController extends Controller {
/* Here the PUT /apps/cookbook/recipe/{id} endpoint will be routed */
public function update($id){
$json = $this->requestHelper->getJson(); // Call to helper
// Here comes the business logic
// aka calls to other classes that will save and update the state
// and perform the DB operation
$this->service->doSomething($json);
// Return an answer if the operation terminated successfully
return JsonResponse(['state'=>'ok'], 200);
}
}
I want to test the getJson() method against different servers. Here I want to mock at least the $this->service->doSomething($json) to be a no-op. Ideally, I would like to spy into the resulting $json variable to test that exactly.
No doubt, in my test class it would be something like
class TestResponseHandler extends TestCase {
public function setUp() { /* Set up the http deamon as system service */}
public testGetJson() {
// Creat Guzzle client
$client = new Client([
'base_uri' => 'http://localhost:8080/apps/cookbook',
]);
// Run the API call
$headers = ...;
$body = ...;
$response = $client->put('recipe/15', 'PUT', $headers, $body);
// Check the response body
// ....
}
}
Now, I have two code interpreters running: Once, there is the one (A) that runs phpunit (and makes the HTTP request). Second, there is the one (B) associated with the HTTP server listening on localhost:8080.
As the code above with the call to getJson() is running inside a PHP interpreter (B) outside the phpunit instance I cannot mock directly as far as I understand. I would have to change the main app's code if I am not mistaken.
Of course, I could provide (more or less) useful data in the test function and let the service->doSomething() method do its job but then I am no longer testing only a subset of functions but I am doing functional or system testing. Also, this makes it harder to generate well-aimed test cases if all these side-effects need to be taken into account.