UTBot generates uncompilable Kotlin parametrized tests

[tyuldashev]

Description

When user tries to generate parametrized test for Kotlin code as result she gets uncompilable code

To Reproduce

Steps to reproduce the behavior:

1. Invoke test generation for the code below, with enabled setting Parametrized tests

class A {
    fun f(a:Int, b:Int): Int {
        return a + b;
    }
}

Expected behavior

Executable tests are generated

Actual behavior

Tests cannot be compiled and executed.

Visual proofs (screenshots, logs, images)
Resulted code and errors:

class ATest {
    ///region Test suites for executable org.test.A.f
    
    ///region Parameterized test for method f(int, int)
    
    @ParameterizedTest
    @MethodSource("org.test.ATest#provideDataForF")
    fun parameterizedTestsForF(a: A?,
    a1: Int,
    b: Int,
    expectedResult: Int?
    ) {
        val actual = a.f(a1, b) // #1 error
        
        assertEquals(expectedResult, actual)
    }
    ///endregion
    
    ///endregion
    
    companion object {
        ///region Data providers
        
        @JvmStatic
        fun provideDataForF(): java.util.ArrayList // #2 error
         {
            val argList = java.util.ArrayList() // #3 error
            
            run {
                val a = A()
                
                val testCaseObjects = kotlin.Array<Any?>(4) { null }
                testCaseObjects[0] = a
                testCaseObjects[1] = -1
                testCaseObjects[2] = 1
                testCaseObjects[3] = 0
                argList.add(arguments(testCaseObjects))
            }
            
            return argList
        }
        ///endregion
    }
}

[volivan239]

I believe this is a part of two much bigger issues related to Kotlin type system with its generics (#88) and nullability (no specific issue made yet afaik) and ideally should be fixed after solving those two (thus, this is an important case on which they should be tested)

[EgorkaKulikov]

Parametrized tests are not supported for Kotlin and their support was never declared. In fact, sometimes they really work, but this is just a good luck.
The comment of Vanya explains the reasons.

[tyuldashev]

I think that in any case UTBot should not generate uncompilable code. Otherwise user would have to remove/fix such tests based on no information before she could use generated tests. That could become especially inconvenient in case tests have been generated for the whole project or package.

[EgorkaKulikov]

@alisevych Currently parameterized tests are disabled for Kotlin, we will enable it again after further Kotlin support. I think we should remove this task from 2022.12 Release.