kotlin.Result<T> mocking is not working as expected

[siboxd]

Prerequisites

Please answer the following questions for yourself before submitting an issue.

• I am running the latest version (checked on 1.10.6 and 1.11.0)
• I checked the documentation and found no answer
• I checked to make sure that this issue has not already been filed

Expected Behavior

I expect that mockk treats kotlin.Result<T> class as other classes

Current Behavior

It seems that it is unnecessary wrapping any Result<T> return type to another Result.success instance making even a basic test fail.

Failure Information (for bugs)

I have no useful information at this time... I'll add if I find useful info.

Steps to Reproduce

Let's consider this piece of code:

    class Data

    interface MyInterface {
        fun getData(): Result<Data>
    }

Now I'm gonna test, with a mockk of MyInterface, that it returns the instance of Data class wrapped in a Result.success instance:

    @Test
    fun testWithBug() {
        val myDataResult = Result.success(Data())
        val myInterface = mockk<MyInterface> {
            every { getData() } returns myDataResult
        }

        assertSame(myDataResult, myInterface.getData())
    }

This test fails with:

java.lang.AssertionError: expected same:<Success(com.my.test.MyTest$Data@6e0cff20)> was not:<Success(Success(com.my.test.MyTest$Data@6e0cff20))>
Expected :Success(com.my.test.MyTest$Data@6e0cff20)
Actual   :Success(Success(com.my.test.MyTest$Data@6e0cff20))

But there's no code wrapping the Data() in two successes... from where does it come?

The thing is that it's a problem of the Result class because if you do this, the test passes:

    class Data

    interface MyInterface {
        fun getData(): Data
    }

    @Test
    fun testWithBug() {
        val myDataResult = Data()
        val myInterface = mockk<MyInterface> {
            every { getData() } returns myDataResult
        }

        assertSame(myDataResult, myInterface.getData())
    }

Context

Please provide any relevant information about your setup. This is important in case the issue is not reproducible except for under certain conditions.

• MockK version: 1.10.6 and 1.11.0
• OS: macOS 10.15.7
• Kotlin version: 1.5.10
• JDK version: 1.8.0_282
• JUnit version: 4.13.2
• Type of test: unit test

Minimal reproducible code (the gist of this issue)

// -----------------------[ GRADLE DEFINITIONS ] -----------------------
dependencies {
    testImplementation "junit:junit:4.13.2"
    testImplementation "io.mockk:mockk:1.11.0"
}
// -----------------------[ YOUR CODE STARTS HERE ] -----------------------
package com.my.test

import io.mockk.every
import io.mockk.mockk
import org.junit.Assert.assertSame
import org.junit.Test

class MyTest {
    class Data

    interface MyInterface {
        fun getData(): Result<Data>
    }

    @Test
    fun testWithBug() {
        val myDataResult = Result.success(Data())
        val myInterface = mockk<MyInterface> {
            every { getData() } returns myDataResult
        }

        assertSame(myDataResult, myInterface.getData())
    }
}
// -----------------------[ YOUR CODE ENDS HERE ] -----------------------

[pawelsmagala]

This is known problem, it should be solved by this #633
Now we just need to wait for release.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. If you are sure that this issue is important and should not be marked as stale just ask to put an important label.

[siboxd]

I've seen the new version 1.12.0 of Mockk and I gave it a try.

For some reason the assertSame still gives an assertion error...

expected same:<Success(com.my.test.MyTest$Data@7dd22fe3)> was not:<Success(com.my.test.MyTest$Data@7dd22fe3)>
Expected :Success(com.my.test.MyTest$Data@7dd22fe3)
Actual   :Success(com.my.test.MyTest$Data@7dd22fe3)
<Click to see difference>

Have you tried my use case with the new version 1.12.0?

[b22n]

It is reproduced in 1.12.0 (kotlin 1.5.21 ~ 1.5.31)

[nuhkoca]

This is still occurring in 1.12.0

[milken]

I can confirm it still happens for value class in 1.12.2.
I'm staying on 1.10.2 until resolved :(

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. If you are sure that this issue is important and should not be marked as stale just ask to put an important label.

[siboxd]

Any news on this? Could you put the important label?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. If you are sure that this issue is important and should not be marked as stale just ask to put an important label.

[siboxd]

The issue is still present with: kotlin 1.6.21 and mockk 1.12.4

The assertSame still gives an assertion error...

Any news on this issue? Could you put the important label?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. If you are sure that this issue is important and should not be marked as stale just ask to put an important label.

[siboxd]

Any news on this? Could you put the important label?

[behnawwm]

It's still happening in 1.13.8 and Kotlin 1.9

[aditya-dodda]

Same issue.