I am writing grails integration tests which call out to a controller which call a service which calls another service which calls another service.
Controller -> ServiceA.method1() -> ServiceB.method2() -> ServiceC.method3()
the last method in the last service to be called (ServiceC.method3()) makes a call to the outside world (another JVM) and returns a result, which I want to mock out for my integration test. So I am still testing the chain up to and back from that particular service method.
I was reading up on mocking in grails but it seems that it is only possible in unit testing.
Any tips how to progress this one?
Use the metaClass to override a method's functionality. I do this all the time in my integration tests as my way to mock.
So in your test method do something like this (note that the method arg types must match exactly with the real method):
controller.serviceA.serviceB.serviceC.metaClass.method3 = { Args args ->
// do whatever you want here, set flags to indicate method called,
// assert args, declare return types, etc
// return 'mocked' result
}
Make sure in your integration test tear down method you reset the metaClass of this service otherwise all your other int tests will have the same definition:
controller.serviceA.serviceB.serviceC.metaClass = null
I was reading up on mocking in grails but it seems that it is only
possible in unit testing.
That's certainly not true.
You could use all ways of mocking that are available in Groovy in both unit and integration tests.
With mocking using Map coercion, it can be this easy:
controller.serviceA.serviceB.serviceC = [method3: {return 'MockValue'}] as ServiceC
Related
I have a method:
-(void)startTaskForResult:(long long*)result {
...
}
The function I want to unit test invoke above function:
-(void)doWork {
long long result = 0;
[self startTaskForResult:&result];
}
I am using OCMock library to do unit tests. In my test case, I want to set the result argument to an mocked value e.g. 100 without care about the actual implementation of -(void)startTaskForResult:(long long*)result.
I tried the following way:
-(void)testDoWork{
// try to set 100 to argument 'result'
OCMStub([classToTest startTaskForResult:[OCMArg setToValue:OCMOCK_VALUE((long long){100})]]);
// run the function, but it doesn't use mocked value 100 for argument 'result'
[classToTest doWork];
...
}
But, when I run my test, it does't use the mocked value 100 for argument result. What is the right way to set mocked value to argument in my case then?
Few points to answer your question:
Code for your problem:
- (void)testDoWork
{
id mock = OCMPartialMock(classToTest)
OCMStub([mock startTaskForResult:[OCMArg setToValue:OCMOCK_VALUE((long long){100})]]).andForwardToRealObject;
// set your expectation here
[classToTest doWork];
}
To solve your particular problem:
Your object should be partial mock
Your method should be stubbed (you did it)
Your stub should be forwarded to real object (i assume you need method startTaskForResult: implementation to be called)
However, you face the problems because you are using wrong approach to test;
There're 3 most common strategies to write unit tests:
Arrange-Act-Assert used to test methods
Given-When-Then used to test functions
Setup-Record-Verify used to test side effects. This usually requires mocking.
So:
If you want to test that startTaskForResult: returns particular value - you should call just that and expect return value (not your case, method return type is void)
If method changes the state of object - you should expect that state change, like property value or so
If calling of doWork has a side effect of calling startTaskForResult:, you should stub it and expect it's call, almost like i've written in code above. However (!!!), however you shouldn't expect things like this. This is not a kind of behaviour that has much sense to test, because it's internal class implementation details. One possible case, when both methods are public and it's explicitly stated in class contract, that one method should call another with some preliminary setup. In this case you expect method call with some state / arguments.
To have your application code testable, you require continuously refactoring your code. Some code is untestable, it's probably better to adopt application code rather then try to cover it with tests anyway. You lose the initial goal of tests - refactoring safety and low cost of making changes.
I love the way that you can write clean concise code in Dart, but it appears that Dart is one of those languages that it easy to write but hard to test!
For example, given the following fairly simple method, how does one go about unit testing it?
typedef void HandleWebSocket(WebSocket webSocket);
Router createWebSocketRouter(HttpServer server, String context, HandleWebSocket handler) {
var router = new Router(server);
router.serve(context).transform(new WebSocketTransformer()).listen(handler);
return router;
}
You need to somehow replace the new Router() with some sort of factory method that returns a mock. The mock then needs to return a mock when serve is called. That then needs to have a mock transform* method that returns a mock stream.....and at that point most people will give up!
I have managed to write a unit test using the above approach but as it required 80 odd lines and polluted the actual class with a factory method I can hardly say I am happy with it!
Is there a better way of doing this?
I'm testing a controller and there I defined an action which uses a value from the requestobject.
How can I mock the request object in an integration test?
I know that integration tests don't run in an Servlet, so there is no Requestobject, but how do I obtain it?
Quickest thing is to mock needed methods using Map coercion:
myController.request = [ getHeader: { -> '0' } ]
(that link also includes Expando sample).
If you need extensive Request usage, try functional-test plugin.
so I think I'm perhaps not fully understanding how you would use an IOC container for doing Integration tests.
Let's assume I have a couple of classes:
public class EmailComposer : IComposer
{
public EmailComposer(IEmailFormatter formatter)
{
...
}
...
public string Write(string message)
{
...
return _formatter.Format(message);
}
}
OK so for use during the real application (I'm using autofac here) I'd create a module and do something like:
protected override void Load(ContainerBuilder containerBuilder)
{
containerBuilder.RegisterType<HtmlEmailFormatter>().As<IEmailFormatter>();
}
Makes perfect sense and works great.
When it comes to Unit Tests I wouldn't use the IOC container at all and would just mock out the formatter when I'm doing my tests. Again works great.
OK now when it comes to my integration tests...
Ideally I'd be running the full stack during integration tests obviously, but let's pretend the HtmlEmailFormatter is some slow external WebService so I decide it's in my best interest to use a Test Double instead.
But... I don't want to use the Test Double on all of my integration tests, just a subset (a set of smoke-test style tests that are quick to run).
At this point I want to inject a mock version of the webservice, so that I can validate the correct methods were still called on it.
So, the real question is:
If I have a class with a constructor that takes in multiple parameters, how do I make one of the parameters resolve to a an instance of an object (i.e. the correctly setup Mock) but the rest get populated by autofac?
I would say you use the SetUp and TearDown (NUnit) or ClassInitialize and ClassCleanup (MSTest) for this. In initialize you register your temporary test class and in cleanup you restore to normal state.
Having the DI container specify all the dependencies for you has the benefit of getting an entire object graph of dependencies resolved. However if there's a single test in which you want to use a different implementation I would use a Mocking framework instead.
I'd like to test a "withCriteria" closure and am not sure how to go about it. I see how to mock out the withCriteria call, but not test the code within the closure. When running the test that executes the "withCriteria", I keep getting a MissingMethodException, even though the code runs fine under the normal flow of execution. Any ideas?
Thanks!
Steve
I wouldn't go that route. Instead I'd move the query into the domain class as a static finder method and test it directly in an integration test with real data. Then you can easily mock the helper method when it's called in a controller or service test.
class YourDomainClass {
...
static List<YourDomainClass> findFooBar() {
YourDomainClass.withCriteria {
...
}
}
}
Then in a unit test:
def results = [instance1, instance2, instance3]
YourDomainClass.metaClass.static.findFooBar = { -> results }
This way you test that the query works against the in-memory database in an integration test but it's easy to mock it in unit tests.
Further to Burt's answer, check out named queries as described here:
http://blog.springsource.com/2010/05/24/more-grails-1-3-features/
You can then mock the property/method access in your unit tests as described by Burt.
Since nobody mentioned the option to create a DSL to run other DSLs here's a full disclosure of this method. I use it quite often with very good results.
Groovy/Grails testing DSLs
There's no mock implementation for Hibernate criteria at the present time. You'll need to use integration tests. However, Burt's recommendation of making this a static finder method is a good one for code organization. You should also look at named queries, described at http://www.grails.org/1.2+Release+Notes, for a nice syntax for this.