Clarify Junit 5 test imports

Fix #14

README.adoc

@@ -270,12 +270,14 @@ dependencies {
 }
 ----
 
-Refresh Gradle configuration, and open `BlogApplicationTests` to replace `@RunWith(SpringRunner::class)` by `@ExtendWith(SpringExtension::class)`.
+Refresh Gradle configuration, open `BlogApplicationTests` and update imports as bellow and remove `@RunWith(SpringRunner::class)` since `@SpringBootTest` is already annotated with JUnit 5 `@ExtendWith(SpringExtension::class)` as of Spring Boot 2.1.
 
 `src/test/kotlin/blog/BlogApplicationTests.kt`
 [source,kotlin]
 ----
-@ExtendWith(SpringExtension::class)
+import org.junit.jupiter.api.Test
+import org.springframework.boot.test.context.SpringBootTest
+
 @SpringBootTest
 class BlogApplicationTests {
 

src/test/kotlin/blog/BlogApplicationTests.kt

@@ -1,11 +1,8 @@
 package blog
 
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.ExtendWith
 import org.springframework.boot.test.context.SpringBootTest
-import org.springframework.test.context.junit.jupiter.SpringExtension
 
-@ExtendWith(SpringExtension::class)
 @SpringBootTest
 class BlogApplicationTests {
 

src/test/kotlin/blog/HttpApiTests.kt

@@ -2,10 +2,8 @@ package blog
 
 import com.nhaarman.mockito_kotlin.whenever
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.ExtendWith
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
-import org.springframework.test.context.junit.jupiter.SpringExtension
 import org.springframework.boot.test.mock.mockito.MockBean
 import org.springframework.test.web.servlet.MockMvc
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
@@ -13,7 +11,6 @@ import org.mockito.Mockito.any
 import org.springframework.http.MediaType
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.*
 
-@ExtendWith(SpringExtension::class)
 @WebMvcTest
 // TODO Use constructor-based val property for @MockBean when supported, see issue spring-boot#13113
 class HttpApiTests(@Autowired val mockMvc: MockMvc) {

src/test/kotlin/blog/IntegrationTests.kt

@@ -4,16 +4,12 @@ import org.assertj.core.api.Assertions.*
 import org.junit.jupiter.api.AfterAll
 import org.junit.jupiter.api.BeforeAll
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.ExtendWith
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.boot.test.web.client.TestRestTemplate
 import org.springframework.boot.test.web.client.getForEntity
-import org.springframework.boot.test.web.client.getForObject
 import org.springframework.http.HttpStatus
-import org.springframework.test.context.junit.jupiter.SpringExtension
 
-@ExtendWith(SpringExtension::class)
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
 class IntegrationTests(@Autowired val restTemplate: TestRestTemplate) {
 

src/test/kotlin/blog/RepositoriesTests.kt

@@ -2,13 +2,10 @@ package blog
 
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.ExtendWith
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
 import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager
-import org.springframework.test.context.junit.jupiter.SpringExtension
 
-@ExtendWith(SpringExtension::class)
 @DataJpaTest
 class RepositoriesTests(@Autowired val entityManager: TestEntityManager,
 						@Autowired val userRepository: UserRepository,