I'm working on a scala project and in my unit test I have to stub a method that takes as argument a Date(that is instanciated when calling the method), and I can't get to stub it porperly
However, I was able to find a turnaround using this post How to mock new Date() in java using Mockito
But I wonder if there is a better way to do this because I find that solution not very satisfying ...
here is the code I try to stub :
def foo(): Future[JsonObject] ={
[...]
for {
a <- b.bar(arg,atDate = Some(Date.from(Instant.now())))
} yield a
}
I tried to stub it like that
val b = mock[B]
when(b.bar(arg, _:Option[Date])).thenReturn(Future.successful(List()))
this doesn't parse,so I have to change it to :
val b = mock[B]
when(b.bar(arg, _:Option[Date])).thenReturn({ d:Date => Future.successful(List())})
and when I run it I have the following error :
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods *cannot* be stubbed/verified.
Mocking methods declared on non-public parent classes is not supported.
2. inside when() you don't call method on mock but on some other object.
org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods *cannot* be stubbed/verified.
Mocking methods declared on non-public parent classes is not supported.
2. inside when() you don't call method on mock but on some other object.
Maybe I'm missing something in the error message but I don't find it helpful.
Is there any way to tell the stub to take whatever value for the date?
Also why does it require to put a function in thenReturn part, although the return type of the function is Future[List[A]]?
thanks in advance
You have to use the any matcher, so your code looks like (here I'm assuming arg is a variable defined somewhere else in your test code)
when(b.bar(ArgumentMatchers.eq(arg), ArgumentMatchers.any())).thenReturn(Future.successful(List()))
Now that's a bit verbose, so if you upgrade to mockito-scala and use the idiomatic syntax it would look like
b.bar(arg, *) returns Future.successful(List())
if you have/use cats, you can even do
b.bar(arg, *) returnsF List()
for more info check the docs here
Related
So I want to check arguments that I send to an external class that I do not control. The external class is assumed tested, I simply want to test if I passed it the right parameters. I have tried some combination of ArgumentCaptor etc, but not much luck
import org.ABC.ExternalClass
case class Foo(i:Int, j: Int...) {
val EC = CreateExternalClass()
def CreateExternalClass(): ExternalClass = {
new ExternalClass (i, j, ....many parameters)
}
}
I think you are getting things wrong here: you can only use an ArgumentCaptor on calls to mocked objects. You can't use them to "intercept" arbitrary calls between all kinds of objects.
Meaning: you could only use an ArgumentCaptor if you would be using a mocked ExternalClass object. But then you would not need to capture, as you probably could do simply method call argument verification.
But of course, you can't use Mockito to mock that call to new in your production class. The options you have:
Turn to PowerMockito or JMockit; frameworks that allow to mock calls to new. Not recommended.
Rework your production code to not do that call to new. Probably not helpful here; as this class might already be a wrapper around that external class
Go for checking on the created object: check if you could use getter methods to simply query the newly created object to have the values that you expect to show up inside
I am pretty new to Scala and I am learning Play as well. I see the following construct used in Play
def list = Action {
val products = Product.findAll
Ok(views.html.products.list(products))
}
I am confused as to what
Action {}
does. Is Action the returned value of the method? What is this construct called if I want to know more about it?
This construction called factory method enhanced via scala apply sugar
Action in this reference is the companion object, which could be called singleton, but in fact along with very specific singleton type Action$ it methods reflected as static methods of Action.
As we can read object Action extends ActionBuilder[Request] which have plenty of apply methods constructing values of Action type.
Curly braces here presents nullary function which is null-parameter closure and often named so in different languages like ruby or groovy. It's just multiline block of code which produces something at the end.
I've got a signature for a method that looks like this:
private IEnumerable BuildCustomerUpdatePlan(List localCacheChangedCustomers, List crmChangedCustomers){}
When I look at the moled object, the syntax (IntelliSense) of how to call the method and test itis absolutely confusing to me and every time I give it a shot, I get compilation errors. I've looked through the basic tutorials provided on MSFT's site, but I simply don't get how to test a private method using Moles or how to deal with the return type and multiple parameters.
Unfortuantely I've been unable to find other good HOWTO's or threads demonstrating a more complex sample than just working with a simple Add() method that spits out an INT and accepts an INT. :(
Tips?
In your testing project, first make sure you add a Moles assembly corresponding to the assembly-under-test. You'll also want to add an using statement of the assembly-under-test with .Moles appended so you can use the moled assembly.
Moles changes the names of the classes and methods to the form M[Original Class Name].[Original Method Name][typeof param1][typeof param2].... In your case a detour for that method could look like MClass.BuildCustomerUpdatePlanListList = (List x, List y) => { [code]};. That defines an anonymous method that takes two Lists as parameters and you'd put whatever code wanted in the function. Just make sure that you return an IEnumerable in that anonymous method.
Here's an example using Moles to detour Directory.GetFiles:
using System.IO.Moles;
[assembly: MoledType(typeof(System.IO.Directory))]
...
MDirectory.GetFilesStringString = (string x, string y) => new string[0];
Since the Directory class is a member of System.IO I use using System.IO.Moles; to specify that I want to use moled members of the assembly.
Moles requires you to specify the types Moled: [assembly: MoledType(typeof(System.IO.Directory))] does the job.
Finally, Directory.GetFiles takes two strings as parameters and returns a string array. To detour the method into returning the equivalent of no files found, the moled method just returns new string[0]. Curly braces are needed if you want multiple lines in the anonymous method and, if not detouring a void method, a return statement that matches the type the original method would return.
Is it possible to create an AOP like interceptor using Scalas new Dynamic Type feature? For example: Would it be possible to create a generic stopwatch interceptor that could be mixed in with arbitrary types to profile my code? Or would I still have to use AspectJ?
I'm pretty sure Dynamic is only used when the object you're selecting on doesn't already have what you're selecting:
From the nightly scaladoc:
Instances x of this trait allow calls x.meth(args) for arbitrary method names meth and argument lists args. If a call is not natively supported by x, it is rewritten to x.invokeDynamic("meth", args)
Note that since the documentation was written, the method has been renamed applyDynamic.
No.
In order for a dynamic object to be supplied as a parameter, it'll need to have the expected type - which means inheriting from the class you want to proxy, or from the appropriate superclass / interface.
As soon as you do this, it'll have the relevant methods statically provided, so applyDynamic would never be considered.
I think your odds are bad. Scala will call applyDynamic only if there is no static match on the method call:
class Slow {
def doStuff = //slow stuff
}
var slow = new Slow with DynamicTimer
slow.doStuff
In the example above, scalac won't call applyDynamic because it statically resolved your call to doStuff. It will only fall through to applyDynamic if the method you are calling matches none of the names of methods on the type.
In RhinoMocks, there's Stub extension method, that takes Action<T>. For some reason this:
CurrentInvoice.Stub(i => i.TaxYear).Return(1);
works great, but this:
CurrentInvoice.Stub(new Action<Invoice>(i => i.TaxYear)).Return(1);
produces the compiler error:
Only assignment, call, increment, decrement, and new object expressions can be used as a statement
The intellisense for this method explicitly says that it expects Action<Invoice>, so I can't understand why the first works, but not the second.
The main relevance of this is that I'd like to be able to pass some of these configuration lambdas as parameters to a method, and I run into this same issue.
Thanks
Are you sure you're not accidentally using an overload for Stub which takes a Func<T, TResult> in the first line? I can't see why the first call would work otherwise.
Do you have a link to API documentation?