I have a data class A with a function as follows:
data class A(val a: String) {
fun foo(b: String) = "$a, $b"
}
I attempt the following mock in my test:
fun `whatever`() {
val spy = spyk<A>()
every { spy.a } returns "Tree"
assertThat(spy.foo("Snake")).isEqualTo("Tree Snake")
}
When I run a test written like this it fails with a NullPointerException on the line fun foo... in the data class.
Am I doing anything wrong or is this a bug in MockK?
I have totally different results when I run your code. Firstly it complains that there is no default constructor.
Then I fixed it to use the non-default constructor and it prints "abc Snake"
val spy = spyk(A("abc"))
every { spy.a } returns "Tree"
println(spy.foo("Snake"))
There is a reason for that. Kotlin is accessing a property through a field in foo function. This seems to be an optimization.
MockK is not able to do anything about it right now. There is the following ticket to transform getfield call: https://github.com/mockk/mockk/issues/104
Related
I have the following piece of code in Kotlin (using WebFlux), which I wanna test:
fun checkUser(user: People.User?): Mono<Unit> =
if (user==null) {
Mono.empty()
} else {
webClient.get().uri {
uriBuilder -> uriBuilder
//... building a URI
}.retrieve().bodyToMono(UserValidationResponse::class.java)
.doOnError {
//log something
}.map {
if (!item.isUserValid()) {
throw InvalidUserException()
}
}
}
My unit test so far looks like this:
#Test
fun `Returns error when user is invalid`() {
val user = People.User("name", "lastname", "street", "zip code")
//when
StepVerifier.create(checkUser(user))
//then
.expectError(InvalidUserException::class.java)
.verify()
}
However when I run it, it throw the following error:
io.mockk.MockKException: no answer found for: WebClient(#1).get()
at io.mockk.impl.stub.MockKStub.defaultAnswer(MockKStub.kt:90)
at io.mockk.impl.stub.MockKStub.answer(MockKStub.kt:42)
at io.mockk.impl.recording.states.AnsweringState.call(AnsweringState.kt:16)
at io.mockk.impl.recording.CommonCallRecorder.call(CommonCallRecorder.kt:53)
at io.mockk.impl.stub.MockKStub.handleInvocation(MockKStub.kt:263)
at io.mockk.impl.instantiation.JvmMockFactoryHelper$mockHandler$1.invocation(JvmMockFactoryHelper.kt:25)
at io.mockk.proxy.jvm.advice.Interceptor.call(Interceptor.kt:20)
I guess the error occurs because I havent mocked WebClient(#1).get() but I am not sure how to mock it. So far I have tried:
every { webClient.get() } returns WebClient.RequestHeadersUriSpec
but it doesnt compile. The error says:
Classifier 'RequestHeadersUriSpec' does not have a companion object, and thus must be initialized here
Someone knows how I can mock WebClient(#1).get()? Thanks in advance
Basically you need something like this:
mock ResponseSpec - mock the body or error in whichever way you need for the respective test case
mock RequestHeadersUriSpec - let the retrieve() method return the ResponseSpec mock
mock WebClient - let the get() method return the RequestHeadersUriSpec mock
Here is a full example:
val response = mockk<WebClient.ResponseSpec>()
val spec = mockk<WebClient.RequestHeadersUriSpec<*>>()
val client = mockk<WebClient>()
every { response.bodyToMono(String::class.java) } returns Mono.just("Hello StackOverflow")
every { spec.retrieve() } returns response
every { client.get() } returns spec
println(client.get().retrieve().bodyToMono(String::class.java).block())
This will correctly print the Hello StackOverflow string.
Though it may be a "historical" question, I actually also had this problem recently.
Just as what Krause mentioned, the full call path of WebClient should be mocked. This means the method stream in every{} block should as the same as WebClient call. In your case, it may be something like
every{webClient.get().uri {???}.retrieve().bodyToMono(???)} returns Mono.just(...)
The next question is something about the error message io.mockk.MockKException: no answer found for: RequestBodyUriSpec(#3).uri(......). The key to the question is methods with parameters and without parameters are totally different things.
Thus, for target method, a uri(Function<UriBuilder, URI> uriFunction) is called(a lambda expression is used here to instead of Function interface). However, for mock method, a uri() method without any parameter is called. This is why the error message said , "no answer found for ...". Therefore, in order to match the mocked method, the code should be:
every{webClient.get().uri(any<java.util.function.Function<UriBuilder, URI>>()).retrieve().bodyToMono(???)} returns Mono.just(...)
Or, the any() method can be changed to the real URI which should be as the same as the target method.
Similarly, bodyToMono() should also be mocked with the correct parameter, which may be bodyToMono(any<ParameterizedTypeReference<*>>()).
Finally, the mock code may look like:
every{client.get()
.uri(any<java.util.function.Function<UriBuilder, URI>>())
.retrieve().bodyToMono(any<ParameterizedTypeReference<*>>())}
return Mono.just(...)
I'm trying to write a Jasmine test for a function of class which instantiates and observes an object from another class. Since I want to keep this test contained to the first class and to simulate different scenarios of the second I want to mock the second. Some pseudo code might help
export class Foo {
startProcessing() {
const bar = new Bar();
const sub = bar.tickTock.subscribe(
state => {
// something went right
},
error => {
// something went wrong
}
);
}
}
I've tried declaring the mock class in my test file, and providing it through TestBed.configureTestingModule's providers attribute, but it always uses the original Bar.
How can I write a test that provides a mock class in place of Bar that I can control?
One way to get around this issue is to pass in object of type Bar through function parameter (dependency injection). That way you can have control over Bar object.
So, while this is quite a kotlin-dsl for gradle specific issue, I think it overall applies to the kotlin language itself, so I am not going to use that tag.
In the gradle API, the class Action<T> is defined as:
#HasImplicitReceiver
public interface Action<T> {
/**
* Performs this action against the given object.
*
* #param t The object to perform the action on.
*/
void execute(T t);
}
So ideally, this should work in kotlin (because it is a class with a SAM):
val x : Action<String> = {
println(">> ${it.trim(0)}")
Unit
}
But I get the following two errors:
Unresolved reference it
Expected Action<String> but found () -> Unit
Fwiw, even Action<String> = { input: String -> ... } doesn't work.
Now here's the really intriguing part. If I do the following in IntelliJ (which btw, works):
object : Action<String> {
override fun execute(t: String?) {
...
}
}
IntelliJ pops the suggestion Convert to lambda, which when I do, I get:
val x = Action<String> {
}
which is better, but it is still unresolved. Specifying it now:
val x = Action<String> { input -> ... }
gives the following errors Could not infer type for input and Expected no parameters. Can someone help me with what is going on?
This is because the Action class in gradle is annotated with HasImplicitReceiver. From the documentation:
Marks a SAM interface as a target for lambda expressions / closures where the single parameter is passed as the implicit receiver of the invocation (this in Kotlin, delegate in Groovy) as if the lambda expression was an extension method of the parameter type.
(emphasis mine)
So, the following compiles just fine:
val x = Action<String> {
println(">> ${this.trim()}")
}
You could even just write ${trim()} and omit the this in front of it.
You need reference the function with class name, like:
val x: Action<String> = Action { println(it) }
I can't seem to figure out how to set a property on a mocked Service in a Service unit test. I've tried using the demand object and the setProperty method which seems to be gone from Grails 2.
#TestFor(SomeService)
#Mock([HelperService])
class SomeServiceTests {
void testDoSomething() {
def helperService = mockFor HelperService
// tried this, error in method being tested
helperService.setProperty('propToSet',['a','b'])
// tried this, error in test
helperService.demand.propToSet = ['a','b']
// tried this, error in method being tested
helperService.demand.getPropToSet() {['a','b']}
service.helperService = helperService
assert service.doSomething('aa') != null
}
}
For most of these the error is No such property: propToSet for class: grails.test.GrailsMock, thrown from within the method I'm testing that needs it. The second option above actually gives a hard error. How do I set a property in a mocked Grails object?
I also have not-that-good experiences with Grails mocking facilities. So I've been using GMock and happy with it. GMock plays well with all Grails tests including controllers, services and domain classes as well as Spock's specifications.
To use it, you simply put the following line into grails-app/conf/BuildConfig.groovy:
dependencies {
test 'org.gmock:gmock:0.8.2'
}
And this is the GMock version of your code.
#WithGMock
#TestFor(SomeService)
class SomeServiceTests {
void testDoSomething() {
def helperService = mock(HelperService)
helperService.propToSet.returns(['a', 'b'])
service.helperService = helperService
play {
assert service.doSomething('aa') != null
}
}
}
Note that your mock codes will have affects only in the play { } block. So we need the block to wrap around assert statements.
EDIT: Please let me be clear, I'm asking how to do this in Grails using Spring Dependency Injection, and NOT Grails' metaclass functionality or new().
I have a grails service that is for analyzing log files. Inside the service I use the current time for lots of things. For unit testing I have several example log files that I parse with this service. These have times in them obviously.
I want my service, DURING UNIT TESTING to think that the current time is no more than a few hours after the last logging statement in my example log files.
So, I'm willing to this:
class MyService {
def currentDate = { -> new Date() }
def doSomeStuff() {
// need to know when is "right now"
Date now = currentDate()
}
}
So, what I want to be able to do is have currentDate injected or set to be some other HARDCODED time, like
currentDate = { -> new Date(1308619647140) }
Is there not a way to do this with some mockWhatever method inside my unit test? This kind of stuff was super easy with Google Guice, but I have no idea how to do it in Spring.
It's pretty frustrating that when I Google "grails dependency injection" all I find are examples of
class SomeController {
// wow look how amazing this is, it's injected automatically!!
// isn't spring incredible OMG!
def myService
}
It feels like all that's showing me is that I don't have to type new ...()
Where do I tell it that when environment equals test, then do this:
currentDate = { -> new Date(1308619647140) }
Am I just stuck setting this property manually in my test??
I would prefer not to have to create a "timeService" because this seems silly considering I just want 1 tiny change.
Groovy is a dynamic language, and as such it allows you to do almost what you're asking for:
class MyServiceTests extends GrailsUnitTestCase {
def testDoSomeStuff() {
def service = new MyService()
service.currentDate = { -> new Date(1308619647140) }
// assert something on service.doSomeStuff()
}
}
Keep in mind this only modifies the service instance, not the class. If you need to modify the class you'll need to work with the metaClass. Take a look at this post by mrhaki.
Another option would be to make the current date a parameter to doSomeStuff(). That way you wouldn't need to modify your service instance.
Thanks for the help guys. The best solution I could come up with for using Spring DI in this case was to do the following in
resources.groovy
These are the two solutions I found:
1: If I want the timeNowService to be swapped for testing purposes everywhere:
import grails.util.GrailsUtil
// Place your Spring DSL code here
beans = {
if (GrailsUtil.environment == 'test') {
println ">>> test env"
timeNowService(TimeNowMockService)
} else {
println ">>> not test env"
timeNowService(TimeNowService)
}
}
2: I could do this if I only want this change to apply to this particular service:
import grails.util.GrailsUtil
// Place your Spring DSL code here
beans = {
if (GrailsUtil.environment == 'test') {
println ">>> test env"
time1(TimeNowMockService)
} else {
println ">>> not test env"
time1(TimeNowService)
}
myService(MyService) {
diTest = 'hello 2'
timeNowService = ref('time1')
}
}
In either case I would use the service by calling
timeNowService.now().
The one strange, and very frustrating thing to me was that I could not do this:
import grails.util.GrailsUtil
// Place your Spring DSL code here
beans = {
if (GrailsUtil.environment == 'test') {
println ">>> test env"
myService(MyService) {
timeNow = { -> new Date(1308486447140) }
}
} else {
println ">>> not test env"
myService(MyService) {
timeNow = { -> new Date() }
}
}
}
In fact, when I tried that I also had a dummy value in there, like dummy = 'hello 2' and then a default value of dummy = 'hello' in the myService class itself. And when I did this 3rd example with the dummy value set in there as well, it silently failed to set, apparently b/c timeNow blew something up in private.
I would be interested to know if anyone could explain why this fails.
Thanks for the help guys and sorry to be impatient...
Since Groovy is dynamic, you could just take away your currentDate() method from your service and replace it by one that suits your need. You can do this at runtime during the setup of your test.
Prior to having an instance of MyService instantiated, have the following code executed:
MyService.metaClass.currentDate << {-> new Date(1308619647140) }
This way, you can have a consistent behavior across all your tests.
However, if you prefer, you can override the instance method by a closure that does the same trick.
Let me know how it goes.
Vincent Giguère