@RestClientTest(IsbnLookupClient.class), base URL from application.properties

lookup(9780134685991) -> Optional[IsbnInfo[isbn=9780134685991, title=Effective Java, author=Joshua Bloch, pages=412]]
lookup(0000000000)    -> Optional.empty

beans in this context:
  BookController (@RestController)=no
  ApiExceptionHandler (@ControllerAdvice)=no
  PriceJson (@JacksonComponent)=yes
  MockMvc=no
  JsonMapper (Jackson 3)=yes
  BookService (@Service)=no
  BookRepository (Spring Data)=no
  EntityManagerFactory=no
  DataSource=no
  RestClient.Builder=yes
  IsbnLookupClient (@Component)=yes
  AuditLogger (@Component)=no
  bean definitions=53