Hi, I've updated Mockk to the latest, also updated Kotlin to 2.0.0, and now here's my issue:

interface X<T: Comparable<T>> {
    fun get(): T
}

@Test
fun `test x`() {
    val x = mockk<X<Int>>()
    
    every { x.get() } returns 1 # fails
    every { x.get().hint(Int::class) } returns 1 # fails

    val result = x.get()

    result shouldBe 1

    verify(exactly = 1) {
        x.get()
    }
}

# workaround:
interface TypedX : X<Int>

@Test
fun `test x`() {
    val x = mockk<TypedX>()
    
    every { x.get() } returns 1 # passes

    val result = x.get()

    result shouldBe 1

    verify(exactly = 1) {
        x.get()
    }
}

The error I get:

Class cast exception happened.
Probably type information was erased.
In this case use `hint` before call to specify exact return type of a method.

io.mockk.MockKException: Class cast exception happened.
Probably type information was erased.
In this case use `hint` before call to specify exact return type of a method.

Caused by: java.lang.ClassCastException: class io.mockk.renamed.java.lang.Number$Subclass3 cannot be cast to class java.lang.Comparable (io.mockk.renamed.java.lang.Number$Subclass3 is in unnamed module of loader 'app'; java.lang.Comparable is in module java.base of loader 'bootstrap')
...

I would like to capture a no-arg lambda argument and then invoke it. The problem is that the return type of the lambda is inferred and differs per each invocation. Is there any way how can I construct a mock for this scenario?

fun <T> execute(operation: Operation, contract: ContractDTO, block: () -> T): T

every { execute(any(), any(), captureLambda()) } answers {
   lambda<() -> ???>().invoke()
}

How to specify the

lambda

type so that it can be used for any actual type

T

?

I've run into a funny/strange issue. Not sure it's strongly related to mockk but I've encountered it in that context. I'm using this for comparing recursive structures in tests (using AssertJ):

fun <T> assertEqualsRecursive(actual: T, expected: T, vararg ignoringFields: String) {
    assertThat(actual)
        .usingRecursiveComparison().withStrictTypeChecking().ignoringFields(*ignoringFields)
        .isEqualTo(expected)
}

In my actual test case I'm capturing a list argument into a slot:

val messageValuesSlot = slot<List<SomeType>>()
val actualMessages = messageValuesSlot.captured

and then comparing it with an expected list:

assertEqualsRecursive(actualMessages, listOf(...))

The problem is that thanks to the

withStrictTypeChecking

option the comparison fails with

actual and expected are considered different since the comparison enforces strict type check and expected type java.util.Arrays$ArrayList is not a subtype of actual type java.util.ArrayList

So if I understand it correctly • There are for some reason two

ArrayList

in java.util • The

listOf

constructor uses different

ArrayList

than the mockk when filling the

messageValuesSlot

Why is that? Why mockk doesn't use

listOf

? Is there anything I can do about that other than reverse-engineer mockk and use the same

ArrayList

?

Hi folks. I’m struggling with a mock setup and could use help from someone who has, you know, used Kotlin, Mockk, or Spring Boot before February when I started. 😬 (Details in 🧵 )

Hi. I’m having an issue with mockk/arrow. If my return type is a String, the test passes. If the return type is a value class, I get an error

Inconsistent number of parameters in the descriptor and Java reflection object: 3 != 2

. Common code between the tests are:

data object MyError1
data object MyError2

@JvmInline
value class TestId(val id: String)

Failing code:

class Foo {
  context(Raise<MyError2>)
  suspend fun foo(): TestId {
    return TestId("hello")
  }
}

class Service(private val foo: Foo) {
  context(Raise<MyError1>)
  suspend fun test(): TestId {
    return withError({ MyError1 }) {
      foo.foo()
    }
  }
}

test("test 1") {
      val foo = mockk<Foo>()
      val service = Service(foo)

      coEvery {
        with(any<Raise<Any>>()) {
          foo.foo()
        }
      }.coAnswers { TestId("hello") }

      either {
        service.test()
      }.shouldBeRight()
    }

Passing code (where instead of having a

TestId

return type, I have a

String

return type.

class Foo {
  context(Raise<MyError2>)
  suspend fun foo(): String {
    return "hello" 
  }
}

class Service(private val foo: Foo) {
  context(Raise<MyError1>)
  suspend fun test(): String {
    return withError({ MyError1 }) {
      foo.foo()
    }
  }
}

    test("test 1") {
      val foo = mockk<Foo>()
      val service = Service(foo)

      coEvery {
        with(any<Raise<Any>>()) {
          foo.foo()
        }
      }.coAnswers { "hello" }

      either {
        service.test()
      }.shouldBeRight()
    }

Hello, i have a problem with mockin a List of mock. I’m tring to mock this type:

@MockK
lateinit var mockAnalyticsReporters: List<AnalyticsReporter?>

when using this I recieve this strange error:

class kotlin.Unit cannot be cast to class java.lang.Boolean (kotlin.Unit is in unnamed module of loader 'app'; java.lang.Boolean is in module java.base of loader 'bootstrap')

java.lang.ClassCastException: class kotlin.Unit cannot be cast to class java.lang.Boolean (kotlin.Unit is in unnamed module of loader 'app'; java.lang.Boolean is in module java.base of loader 'bootstrap')

at io.mockk.renamed.java.util.Iterator$Subclass5.hasNext(Unknown Source)

I actually can’t understand what this means. I’m not a very well tester so i need some help. Thanks.

Hey everyone I am facing a weird error when im stubbing a suspend function to return a serialized data My test fails with exception that, it cannot be serialized due to null value This is my stubbing

val user = User(
    displayName = "",
    contactNumber = "",
    location = null,
    email = "",
    profileImageUrl = "",
    connectionCount = 0,
    followersCount = 0,
    id = "",
    summary = "",
    tagline = "",
    slug = "",
    totalExperienceInMonths = 0,
    createdAt = DateHelpers.now,
    isFollowed = false,
)
val resultUser = user.copy(token = Arb.string().
coEvery {
    apiService.createUser(user, "", "")
} returns resultUser

//call function to test
userRepo.createUser(user, "", "")

Which returns fine, when i debug using breakpoints But the function which I am testing, does this internally

preferences.user = json.encodeToString(user)

Which crashes the test, even though the type User is Serializable Stack trace in thread 🧵

Hi. I have an

Enum

class with

kotlinx-serialization

.

@Serializable
enum class Certificate {
  @SerialName("Certificate_A") A
}

For the purposes of testing, I want to add another

Enum

entry.

@SerialName("Certificate_B") B

How do I do that with

mockk

?

Hey, you know, it’s October…. #C046QQFQV2M 🙄 I just added a new issue that would be fairly easy to work on if anyone’s interested: https://github.com/mockk/mockk/issues/1304 (also there are some issues tagged with #C046QQFQV2M that are generally easier than others)

New release! https://github.com/mockk/mockk/releases/tag/1.13.13 🎉 Lots of new contributors, big thanks to @SackCastellon, @Gala Bill, @mgaetan89 and all the others that I wasn’t able to tag :)

Any timeline on when mockK will support KMP?

Is

mockkStatic

safe to use with parallel test execution? I mean the Gradle option

maxParallelForks

. My understanding is it just spawns multiple jvm processes with their own class loaders. As such static mocks from one process shouldn't leak to the other, correct?. As I understand tests are still run sequentially within each process. In reality though we see test failures that look like they leak happens. We use Junit4 and it's Android project.

Got an interesting issue. Apparently roboelectric and mockk do not play well together. Is there any known way to make them work better together. See 🧵

Is there any likelihood of a patch release containing https://github.com/mockk/mockk/pull/1314 any time soon?

Could anyone suggest a workaround to this issue? https://github.com/mockk/mockk/issues/1324

Is anyone else having issues mocking a

value class

return with the 1.13.13 version?

Hey all, I'm verifying calls to a mocked object and I'm getting

io.mockk.MockKException: No other calls allowed in stdObjectAnswer than equals/hashCode/toString

but no clue why this is happening 😓 Has anyone got this exception before? Thanks in advance ✌️

Is there any way to get IntelliJ to realize that properties annotated with

@InjectMockKs

etc. are not, in fact, unused?

Hello lovely Mockkers! In my test, this line where I mock a return from

repository

every { repository.save(any()) } returns fleetEntity

Returns the following after switching JDK from Eclipse Temurin to docker.io/ibm-semeru-runtimes:open-17.0.13_11-jdk

FleetServiceTest > should return created fleet given request() FAILED
    io.mockk.MockKException at FleetServiceTest.kt:44
        Caused by: java.lang.ClassCastException at FleetServiceTest.kt:44

repository interface:

package org.springframework.data.repository;

import java.util.Optional;

@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {
    <S extends T> S save(S entity);

    <S extends T> Iterable<S> saveAll(Iterable<S> entities);

    Optional<T> findById(ID id);

    boolean existsById(ID id);

    Iterable<T> findAll();

    Iterable<T> findAllById(Iterable<ID> ids);

    long count();

    void deleteById(ID id);

    void delete(T entity);

    void deleteAllById(Iterable<? extends ID> ids);

    void deleteAll(Iterable<? extends T> entities);

    void deleteAll();
}

Any ideas as to why this CastException occurs all of a sudden after changing the JDK? This is important because the new JDK image has a significantly smaller memory footprint.

how do I mockk KPropertys from mocked classes?

class Organisation(
    var name: String,
)

val organisation = mockk<Organisation>()
val property: KMutableProperty0<String> = mockk()

every { organisation::name } returns property

this does not work because the every { ... } call does not contain a mocked call

Did the spring ninja squad mockkbean library move to another maintainer? Is there any changes around it now that old java mockbean has been deprecated in favor of mockitobean?

On the website there is this example:

every { 
    constructedWith<MockCls>(OfTypeMatcher<String>(String::class)).add(2) // Mocks the constructor which takes a String
} returns 3

Why does

OfTypeMatcher

need to have the type

String

mentioned twice? If it was defined differently, we would be able to have just

OfTypeMatcher<String>()

(if we used reified generics), or just

OfTypeMatcher(String::class)

. Perhaps I've misunderstood its usage and the two

String

type references don't have to be the same?

I'm having trouble mocking in the presence of value classes. Invalid arguments that don't exist in my code somehow get passed to the value class' constructor, which fails them. They appear to be caused by reflection in mockk. Does anyone have pointers?

Hi! is it possible to mock every function/property that returns a string in class? I have a class where all of methods and properties return string (for string resources) and I want to have something like this:

private val i18n: I18n = mockk<I18n> {
        every<String> { any() } returns ""
    }

hello channel! I’m migrating the publishing process from OSSRH to Maven Central portal as OSSRH is sunsetting at the end of June. I’m currently publishing v1.14.4 which is identical to v1.14.3 that I published a couple days ago, but with the new publishing process. I’d like to have feedback that the two versions are, indeed, identical and that the new publishing process works correctly 🙂

Hi! I wanted to start using mockk in a KMP project but the IDE is alerting me with this message:

Cannot access class 'MockKMatcherScope'. Check your module classpath for missing or conflicting dependencies.

Does anyone have some clue about this? Thank you so much in advance!

Let's say I have a class with some function:

class Bar {
   fun foo(arg1: String, arg2: String? = null) = "Hello World"
}

How can I mock this without providing matchers for all arguments in the function? Essentially I want to do something like this:

every { barMock.foo } returns "Something Else"

Hello, I have a doubt about about thread safety: suppose I'm running the test suite in parallel, so that within the same JVM process test classes are executed by different threads. If a test uses

clearAllMocks()

, is it thread-safe? Will it somehow clear only this class/thread mocks or will it bulldoze everything within the same process? Can it affect the behaviour of another test running in parallel?

I've been trying to mock a

java.io.File

object and it's not going well. I've just seen the documentation that says that this class is restricted by default, and cannot be mocked. I definitely used to be able to... seven years ago! What's the best practice for handling these files in mockk now?

Sorry, me again. Is there any way of listing all the declared mocks? As in, you're convinced that you've set up a mock correctly but

coVerify

insists it was not called.

no answer provided for DynamoDBService(#8).upsertContentNode(eq(domain.com/sources/posts/my-post.md), eq(domain.com), eq(Posts), any(), eq({}), any()))

And yet...

declareMock<DynamoDBService> {
            every { mockDynamoDBService.logger = any() } just runs
            every { mockDynamoDBService.logger } returns mockLogger
            coEvery {
                mockDynamoDBService.upsertContentNode(
                    "domain.com/sources/posts/my-post.md", "domain.com", 
                        SOURCE_TYPE.Posts,
                    any<ContentNode.PostNode>()
                )
            }
        }