using kotlin with spring boot code example

Example: spring boot kotlin

@RunWith(SpringRunner::class)
@SpringBootTest(classes = arrayOf(KotlinDemoApplication::class), 
  webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class KotlinDemoApplicationTests {

    @Autowired
    lateinit var testRestTemplate: TestRestTemplate

    @Test
    fun whenCalled_shouldReturnHello() {
        val result = testRestTemplate
          // ...
          .getForEntity("/hello", String::class.java)

        assertNotNull(result)
        assertEquals(result?.statusCode, HttpStatus.OK)
        assertEquals(result?.body, "hello world")
    }
}