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.