io.mockk.MockKException: Failed matching mocking signature for SignedCall(...) left matchers: [any()] when running with RobolectricTestRunner

Prerequisites

• I am running the latest version
• I checked the documentation and found no answer
• I checked to make sure that this issue has not already been filed

Expected Behavior

The test passes without error.

Current Behavior

When attempting to mock a response for an extension function using mockkStatic and running the test with RobolectricTestRunner, the test fails to run due to MockKException.

Failure Information (for bugs)

Issue only occurs when using either the RobolectricTestRunner or AndroidJUnit4 test runner & the extension function has at least 1 input parameter. Note that when there are no input parameters, the test will still fail, but will not throw this exception.

Steps to Reproduce

1. Create an extension function which takes at least 1 parameter to test. Example: fun TimeUnit.getSome(of: String): String = "GET SOME $of $this!"
2. Create unit test and mock the response for the extension function

class ExampleUnitTest {
    @Test
    fun test() {
        mockkStatic("path.to.pkg.MyExtensionsKt")
        val testable: TimeUnit = mockk {
            every { getSome(any()) } returns "NONE!"
        }
        assertEquals(testable.getSome("of"), "NONE!")
    }
}

1. Run test & verify it passes
2. Change the test runner to use RobolectricTestRunner (i.e. @RunWith(RobolectricTestRunner::class))
3. Run the test again & observe failure

Context

• MockK version: 1.10.2
• OS: MacOS Catalina 10.15.6 (19G2021)
• Kotlin version: 1.3.72
• JDK version: 11
• JUnit version: 4.12
• Robolectric version: 4.4
• Type of test: UNIT

Failure Logs

io.mockk.MockKException: Failed matching mocking signature for
SignedCall(retValue=TimeUnit(#1), isRetValueMock=false, retType=class kotlin.String, self=TimeUnit(#1), method=toString(), args=[], invocationStr=TimeUnit(#1).toString())
left matchers: [any()]

Stack trace

io.mockk.MockKException: Failed matching mocking signature for
SignedCall(retValue=TimeUnit(#1), isRetValueMock=false, retType=class kotlin.String, self=TimeUnit(#1), method=toString(), args=[], invocationStr=TimeUnit(#1).toString())
left matchers: [any()]

	at io.mockk.impl.recording.SignatureMatcherDetector.detect(SignatureMatcherDetector.kt:99)
	at io.mockk.impl.recording.states.RecordingState.signMatchers(RecordingState.kt:39)
	at io.mockk.impl.recording.states.RecordingState.round(RecordingState.kt:31)
	at io.mockk.impl.recording.CommonCallRecorder.round(CommonCallRecorder.kt:50)
	at io.mockk.impl.eval.RecordedBlockEvaluator.record(RecordedBlockEvaluator.kt:59)
	at io.mockk.impl.eval.EveryBlockEvaluator.every(EveryBlockEvaluator.kt:30)
	at io.mockk.MockKDsl.internalEvery(API.kt:92)
	at io.mockk.MockKKt.every(MockK.kt:98)
	at com.molchanov.android.sandbox.ExampleUnitTest.test(ExampleUnitTest.kt:22)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:575)
	at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$0(SandboxTestRunner.java:263)
	at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:89)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)


Process finished with exit code 255

Minimal reproducible code (the gist of this issue)

// -----------------------[ GRADLE DEFINITIONS ] -----------------------
dependencies {
    testImplementation 'junit:junit:4.12'
    testImplementation 'io.mockk:mockk:1.10.2'
    testImplementation 'org.robolectric:robolectric:4.4'
}
// -----------------------[ YOUR CODE STARTS HERE ] -----------------------
## MyExtensions.kt:
package com.molchanov.android.sandbox

import java.util.concurrent.TimeUnit

fun TimeUnit.getSome(of: String): String = "GET SOME $of $this!"

## UnitTest.kt:
package com.molchanov.android.sandbox

import io.mockk.every
import io.mockk.mockk
import io.mockk.mockkStatic
import org.junit.Assert.assertEquals
import org.junit.Test
import org.junit.runner.RunWith
import org.robolectric.RobolectricTestRunner
import org.robolectric.annotation.Config
import java.util.concurrent.TimeUnit

@Config(manifest = Config.NONE)
@RunWith(RobolectricTestRunner::class)
class UnitTest {

    @Test
    fun test() {
        mockkStatic("com.molchanov.android.sandbox.MyExtensionsKt")
        val testable: TimeUnit = mockk {
            every { getSome(any()) } returns "NONE!"
        }
        assertEquals(testable.getSome("of"), "NONE!")
    }
}
// -----------------------[ YOUR CODE ENDS HERE ] -----------------------

[GladeDiviney]

Still reproducible with Mockk 1.10.6 and Robolectric 4.5.1.

[BelooS]

This issue is still reproducible, please check @Raibaz