Is there a way to use Spring Security-based annotations on Kotest tests?

should work the same way as junit's injection

OK. My IDE complains "This annotation is not applicable to target 'expression'".

Could you show us an example on how you are setting the test up?

I built an example. I can upload the repo to github if it helps.

package org.springframework.security.samples

import io.kotest.core.spec.style.StringSpec
import io.kotest.matchers.shouldBe
import org.assertj.core.api.Assertions
import org.junit.jupiter.api.extension.ExtendWith
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.security.test.context.support.WithMockUser
import org.springframework.test.context.junit.jupiter.SpringExtension
import org.springframework.test.web.servlet.MockMvc
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders
import org.springframework.test.web.servlet.result.MockMvcResultMatchers

@ExtendWith(SpringExtension::class)
@SpringBootTest
@AutoConfigureMockMvc
class KotestSecurity( mockMvc: MockMvc) : StringSpec({

    @WithMockUser
    "dont need login" {
        val mvcResult = mockMvc.perform(MockMvcRequestBuilders.get("/user/index"))
            .andExpect(MockMvcResultMatchers.status().isOk())
    }

    "need login" {
        val mvcResult = mockMvc.perform(MockMvcRequestBuilders.get("/user/index"))
            .andExpect(MockMvcResultMatchers.status().is3xxRedirection())
            .andReturn()
    }
})

I believe

@WithMockUser

should go on the class instead of the test function

That works as a workaround. In the example, the second test fails, because it should test the scenario of not being logged in. But as a workaround you could split your tests into more separate classes.

I see

If I am using a custom Spring-derived annotation, could that work?