aem-mocks property test a servlet - unit-testing

Question

Trying to write some proper AEM integration tests using the aem-mocks framework. The goal is to try and test a servlet by calling its path,
E.g. an AEM servlet
#SlingServlet(
paths = {"/bin/utils/emailSignUp"},
methods = {"POST"},
selectors = {"form"}
)
public class EmailSignUpFormServlet extends SlingAllMethodsServlet {
#Reference
SubmissionAgent submissionAgent;
#Reference
XSSFilter xssFilter;
public EmailSignUpFormServlet(){
}
public EmailSignUpFormServlet(SubmissionAgent submissionAgent, XSSFilter xssFilter) {
this.submissionAgent = submissionAgent;
this.xssFilter = xssFilter;
}
#Override
public void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) throws IOException {
String email = request.getParameter("email");
submissionAgent.saveForm(xssFilter.filter(email));
}
}
Here is the corresponding test to try and do the integration testing. Notice how I've called the servlet's 'doPost' method, instead of 'POST'ing via some API.
public class EmailSignUpFormServletTest {
#Rule
public final AemContext context = new AemContext();
#Mock
SubmissionAgent submissionAgent;
#Mock
XSSFilter xssFilter;
private EmailSignUpFormServlet emailSignUpFormServlet;
#Before
public void setup(){
MockitoAnnotations.initMocks(this);
Map<String,String> report = new HashMap<>();
report.put("statusCode","302");
when(submissionAgent.saveForm(any(String.class)).thenReturn(report);
}
#Test
public void emailSignUpFormDoesNotRequireRecaptchaChallenge() throws IOException {
// Setup test email value
context.request().setQueryString("email=test.only#mail.com");
//===================================================================
/*
* WHAT I END UP DOING:
*/
// instantiate a new class of the servlet
emailSignUpFormServlet = new EmailSignUpFormServlet(submissionAgent, xssFilter);
// call the post method (Simulate the POST call)
emailSignUpFormServlet.doPost(context.request(),context.response());
/*
* WHAT I WOULD LIKE TO DO:
*/
// send request using some API that allows me to do post to the framework
// Example:
// context.request().POST("/bin/utils/emailSignUp") <--- doesn't exist!
//===================================================================
// assert response is internally redirected, hence expected status is a 302
assertEquals(302,context.response().getStatus());
}
}
I've done a lot of research on how this could be done (here) and (here), and these links show a lot about how you can set various parameters for context.request() object. However, they just don't show how to finally execute the 'post' call.

Answer 1

What you are trying to do is mix a UT with IT so this won't be easy at least with the aem-mocks framework. Let me explain why.
Assuming that you are able to call your required code
/*
* WHAT I WOULD LIKE TO DO:
*/
// send request using some API that allows me to do post to the framework
// Example:
// context.request().POST("/bin/utils/emailSignUp") <--- doesn't exist!
//===================================================================
Your test will end up executing all the logic in SlingAllMethodsServlet class and its parent classes. I am assuming that this is not what you want to test as these classes are not part of your logic and they already have other UT/IT (under respective Apache projects) to cater for testing requirements.
Also, looking at your code, bulk of your core logic resides in following snipper
String email = request.getParameter("email");
submissionAgent.saveForm(xssFilter.filter(email));
Your UT criteria is already met by the following line of your code:
emailSignUpFormServlet.doPost(context.request(),context.response());
as it covers most of that logic.
Now, if you are looking for proper IT for posting the parameters and parsing them all the way down to doPost method then aem-mocks is not the framework for that because it does not provide it in a simple way.
You can, in theory, mock all the layers from resource resolver, resource provider and sling servlet executors to pass the parameters all the way to your core logic. This can work but it won't benefit your cause because:
Most of the code is already tested via other UT
Too many internal mocking dependencies might make the tests flaky or version dependant.
If you really want to do pure IT, then it will be easier to host the servlet in an instance and access it via HttpClient. This will ensure that all the layers are hit. A lot of tests are done this way but it feels a bit heavy handed for the functionality you want to test and there are better ways of doing it.
Also the reason why context.request().POST doesn't exist is because context.request() for is a mocked state for the sake of testing. You want to actually bind and mock Http.Post operations which needs some way to resolve to your servlet and that is not supported by the framework.
Hope this helps.