I am trying to write integration test for one of the API in my application which is based on spring webflux. I have integrated an external library which is developed by my organisation and provides support for authentication using JWT tokens.
Custom Validator is defined as

open class CustomValidator {
//Some of the internal classes as fields

}

above class has a function validate which takes two arguments

fun validate(argumentOne: ArgumentOne, argumentTwo: ArgumentTwo? = null)

class which i have created for configuration of integration test is

@TestConfiguration 
class TestSecurityConfig {     
val customValidator: CustomValidator = mockkClass(CustomValidator::class) 
}

The final integration test class is

@SpringBootTest(webEnvironment = RANDOM_PORT) 
@ExtendWith(MockKExtension::class) 
@TestInstance(PER_CLASS)
 @AutoConfigureWebTestClient(timeout = "1d") 
@Import(TestSecurityConfig::class) 

class FunctionalTestClass { 
** THIS IS GIVING ERROR (COULD NOT AUTOWIRE ) IN EDITOR 

@Autowired 
private lateinit var egTokenValidator: EGTokenValidator 

} 
@Test 
fun `testing One` () { 

//This function i am trying to mock  

Mockito.`when`(customeValidator.validate(anyOrNull(), anyOrNull())).thenReturn(validationResult)

//Other code

}

Now when i am running the test case it is not able to mock the class CustomValidator and also giving warning near autowired.
Could you guys please help on how to accomplish this ?
I have not added complete implementation as it is orgranisation code.

I was expecting for the class CustomValidator to be mocked so that i could mock its validator function