DslDemoApplicationTests.kt

@RunWith(SpringRunner::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DslDemoApplicationTests {

    @Autowired
    private lateinit var testRestTemplate: TestRestTemplate

    @Test
    fun `Test 'Hello' endpoint using a valid name`() {
        val headers = HttpHeaders()
        headers.put("Accept", listOf("application/json"))

        val entity = HttpEntity<Any>(headers)

        val response = testRestTemplate.exchange(
           "/api/hello/Jarno", HttpMethod.GET, entity, String::class.java)

        assertEquals(HttpStatus.OK, response.statusCode)
        assertJsonEquals("{ \"message\": \"Hi, Jarno!\" }", response.body)
    }
}