Is it possible to use MockMvc test code to hit a real instance of a web application?
I really like the MockMvc syntax and after going to the efforts of writing a load of code to test controllers, it seems like a duplication of effort to rewrite what would effectively be the same tests using a different API just so I can make an actual HTTP request.
I've got some situations where my MockMvc tests pass, but then the tested behaviour fails when deployed to a web container. This is normally a configuration or environmental issue, and it'd be nice to be able to repeat the same tests to flush those out.
MockMvc is about testing the Controller Layer and it works like a charm .
I think you need Selenium tests to test against a real, deployed application.
Using webdriver (With phantomjs) guarantees that you have the same ease of use as you get with Spring MVC.
But you will have to rewrite your tests to work with webdriver+phantomjs.
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I'm developing a Spring Boot Web API, and I'm currently writing the required units tests.
I was wondering : Isn't writing the units tests (JUnit + Mockito) for the controllers sufficient ? Since the controllers are the entrypoint of my application and that all the logic that is implemented within the Service side is called from the exposed API, why do I need to write test for the Service side ?
First of all, if you write your tests to cover "required level of tests" or requirement to "have some tests at all" having the production implementation already done, it is slightly too late. In the majority of cases having tests first, based on your requirements, contract, use case or anything it more optimal approach. Nevertheless, I don't know your situation and the thing you're trying to implement, so treat it as a suggestion and move on to the key thing you are asking about.
Your JUnit (preferably 5) and Mockito tests, which probably use MockMvc are very good unit(-like) tests to cover web communication concerns such as: HTTP request types, content type, encoding, input and output parameters JSON (de)serialization, error handling, etc. They are best to test with the service layer mocked. Thanks to that you can easily cover a lot of web cases without the need to prepare data in a database, etc.
The core logic has to also be tested. Depending what it is, it might be feasible to test it in the unit way (the easiest to write, can cover a lot of - also corner - cases). It could be supplemented with some set of integration tests to verify that it works fine also in integration (Spring Beans, DB, etc.).
If desired, you may also write some E2E test from the web call via (real) HTTP requests through controllers, services to a database/datastore (if any), but I would limit it only to the most important scenarios to use it in your CI/CD pipeline to verify that a deployment finished successfully.
Disclaimer. I've found this approach useful in multiple situations, but definitely in some other circumstances it might be good to change the balance point to better apply testing.
I think you are probably getting confused between unit and Integration tests.
If you are using Mockito you are probably referring to unit tests wherein, the scope of the Test Class should be only the current class.
Any external method calls should be mocked.So in your case the service calls should be mocked in case you are writing unit test for your controller class.
Your Test Suite should contain
Junit for Controller-- To Test the interface contract points like HTTP Method, Request Parameters, Mandatory inputs, Valid Request Payloads.
Junit for all other classes including Service classes- This is to test your application classes core logic
Integration Test- Finally an integration test which can hit your controller endpoints with service classes and rest of the application code functionality.
We are developing test cases for a micro service using Spring Boot. One of the requirement is that for each Junit test case we need to:
start the project
test a unit case and
then stop the project .
I feel this is an anti pattern, but this is the requirement.
I looked around internet but couldn't find a solution for the same. I was able to start a web server but it provided no response and this might be because the project is not assigned to the server.
Does anyone have any idea on how this can be achieved?
PS: We don't want to use Mockito
Before hand i want to make clear that this a very bad practice and should be avoided. This approach does not implement unit tests concept correctly because you are testing an entire system up, so JUnit wouldn't be the correct tool.
I pocked around and i don't seem to find a Runner that may be able to do this (does not surprise me although), the most similar Runner may be SpringJUnit4ClassRunner which provides you a complete Spring context in your test space, but won't go live with the application.
An approach i'd suggest if you really want to go with this is to use tools like REST Assured to do End-to-End API layer tests against the live application, but this implies that you have to find another way to start the app, and then point the REST Assured tests to that started app. Maybe a shell script that starts the app and then starts the REST Assured tests suits, then when the suit ends put down the server.
I highly suggest you to chat with your product/management teams to avoid this kind of stuff since the tests will take FOREVER to run and you will be polluting your local or remote DBs if you are persisting data or other systems through REST or SOAP calls.
does anybody know why the Spring Boot Guide includes two different types of integration tests? (https://github.com/spring-guides/gs-spring-boot#add-unit-tests)
One with TestRestTemplate and one with MockMvc dependency? In each test type spring boot bootstraps the test environment. So what is the reason for this separation?
When you use MockMvc you are testing an instance of your application in which the HTTP request cycle has been mocked. So, the test scope here is just the MVC aspects of your application. I don't think this would be typically labelled an "integration test", instead it is closer to a unit test (albeit its scope is considerably larger than a single class).
When you use TestRestTemplate you are testing a real instance of your application i.e. you are 'springing up' an entire application context and invoking it as an external actor. This is typically referred to as an "integration test" and it is likely to be the closest test to your actual usage.
Now, since a 'full stack' integration test invoked via TestRestTemplate can provide a superset of the coverage provided by a MockMVC test you might be wondering why you would bother with a MockMVC test. If so, then I think this is a question of ...
Test scope; MockMVC test cases are typically quicker and easier to fire up (since they use less of your application context) than a full integration test. In addition, since they use less of your appolication context you may not have to work as hard to mock out any aspects of your real application context which don't play well in a test.
Ease of use; MockMVC comes with static helpers for asserting HTTP status, interrogating and asserting against JSON responses etc. Of course YMMMV but for many people these faciliate an ease of development and help deliver readable test cases.
In practice, you'll perhaps want to use a combination of both approaches:
MockMVC tests for detailed testing of the entire controller layer including all mappings, happy and sad paths for all invocations and deep assertions on HTTP status codes, content bodies etc
TestRestTemplate tests for the main flows expressed from the users perspective e.g. Save a new Foo, Search for all Foos, Submit an invalid Foo update etc with assertions focussing on the bits which your users see/are interested in.
I have some Spring Boot JUnit tests that require a somewhat lengthy server start up (I'm loading a complex domain in JPA). I've put them into a test suite, but each test kicks off a new server start up.
Is it possible to set them up in such a way that the server is only started once and each test is loaded onto it and run as if the server were started by the test itself?
Okay, so the solution here is actually built in to Spring testing. That is, it caches ApplicationContexts for tests, as described here, as long as the various things like properties are the same.
Ironically, I screwed this up by trying to speed up the tests by using test properties to limit what was loaded.
If I want to unit test my dao classes in spring would I just call my service methods and test those or would you test the service methods separately to the actual dao methods?
Also should I mock the dao calls or actually use an in memory database like H2? I see that as more of an integration test although some tutorials do this, or would a standard approach be to test with mock database objects for the service tests and use H2 when testing the dao calls?
Finally.. My application has a rest API which is called from the web front end using the Spring rest template and so only the API web app accesses the database.
Would I test the rest methods in each web app using mocked objects and then Start a tomcat instance and integration test between the 2 apps? If I used tomcat and ran integration tests between the apps would connect up a database or mock objects in the API app?
Testing the rest calls from the web app relies really on how the API app's rest method responds so is this even worth testing in isolation?
I find unit testing quite confusing as some of it seems almost to be integration testing.
Does it matter if you run integration tests against H2 in memory but then in reality I would be using MySQL?
Trying to answer your questions in the order asked...
For unit testing DAO methods, you should test the actual DAO classes directly with a database in a known state. H2 is great for this, since you can run it without setting up MySQL for each test. Utilizing setup methods with the #Before annotation is great to make sure that the database will respond in expected ways.
For unit testing Service classes, you should mock the DAO classes, so that they will always behave in expected ways. If you use your service and DAO classes with actual data, you are now running integration tests, by testing multiple layers simultaneously. Both have their value, though is generally best to unit test before integration testing, to make sure each component is functioning.
The same goes for testing your controller, you should unit test it and mock the service classes, and then perform integration tests with mock requests to test request/response scenarios. Again, with this test setup you are now testing many layers and classes simultaneously. This is great, because it gives you a good idea of how your application will function in reality, but is not useful for isolating bugs.
H2 and MySQL obviously are not the same, and don't share all the same functionality, so you can't say with 100% confidence that an H2 test will pass in MySQL, but if you are just testing standard CRUD operations, it should do the trick.