MockitoTests_Constructor.kt

import org.hamcrest.MatcherAssert
import org.hamcrest.Matchers
import org.junit.Test
import org.mockito.Mockito
import javax.inject.Inject
import javax.servlet.http.HttpServletRequest


interface Database {
    fun findUser(): User
}

class User(val name: String)

inline fun <reified T : Any> mock() = Mockito.mock(T::class.java)

class MyComponent @Inject constructor(val request: HttpServletRequest, val database: Database) {
    val user: User by lazy {
        database.findUser()
    }

    fun getUsername(): String {
        return user.name
    }
}

class MyComponentTest {

    val request = mock<HttpServletRequest>()
    val database = mock<Database>()
    val sut = MyComponent(request, database)

    @Test
    fun `username`() {
        Mockito.`when`(database.findUser()).thenReturn(User("test"))

        val username = sut.getUsername()

        MatcherAssert.assertThat(username, Matchers.equalTo("test"))
    }
}