Test failures in a Kotlin spring project

Project: https://github.com/spring-guides/tut-spring-boot-kotlin.git

appmap.yml:

# appmap.yml
name: MyFirstKotlin/AppMap

packages:
  # List the packages you'd like to record here.
  - path: com.example.blog

agent.log

Shell output:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.2.RELEASE)

2021-03-23 16:55:21.332  WARN 76617 --- [           main] o.s.boot.StartupInfoLogger               : InetAddress.getLocalHost().getHostName() took 5006 milliseconds to respond. Please verify your network configuration (macOS machines may need to add entries to /etc/hosts).
2021-03-23 16:55:26.340  INFO 76617 --- [           main] com.example.blog.HttpControllersTests    : Starting HttpControllersTests on Ubehebe.local with PID 76617 (started by ptrdvrk in /Users/ptrdvrk/work/github/java/tut-spring-boot-kotlin)
2021-03-23 16:55:26.341  INFO 76617 --- [           main] com.example.blog.HttpControllersTests    : No active profile set, falling back to default profiles: default
2021-03-23 16:55:32.245  INFO 76617 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-03-23 16:55:32.373  INFO 76617 --- [           main] o.s.b.t.m.w.SpringBootMockServletContext : Initializing Spring TestDispatcherServlet ''
2021-03-23 16:55:32.373  INFO 76617 --- [           main] o.s.t.web.servlet.TestDispatcherServlet  : Initializing Servlet ''
2021-03-23 16:55:32.377  INFO 76617 --- [           main] o.s.t.web.servlet.TestDispatcherServlet  : Completed initialization in 4 ms
2021-03-23 16:55:32.393  INFO 76617 --- [           main] com.example.blog.HttpControllersTests    : Started HttpControllersTests in 21.094 seconds (JVM running for 72.569)
2021-03-23 16:55:32.829  WARN 76617 --- [           main] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: no answer found for: Iterable(child of com.example.blog.ArticleRepository#0 bean#2#3).iterator(); nested exception is com.fasterxml.jackson.databind.JsonMappingException: no answer found for: Iterable(child of com.example.blog.ArticleRepository#0 bean#2#3).iterator()]

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /api/article/
       Parameters = {}
          Headers = [Accept:"application/json"]
             Body = <no character encoding set>
    Session Attrs = {}

Handler:
             Type = com.example.blog.ArticleController
           Method = com.example.blog.ArticleController#findAll()

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = org.springframework.http.converter.HttpMessageNotWritableException

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 500
    Error message = null
          Headers = [Content-Type:"application/json"]
     Content type = application/json
             Body =
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
2021-03-23 16:55:32.882  WARN 76617 --- [           main] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: no answer found for: Iterable(child of com.example.blog.UserRepository#0 bean#1#4).iterator(); nested exception is com.fasterxml.jackson.databind.JsonMappingException: no answer found for: Iterable(child of com.example.blog.UserRepository#0 bean#1#4).iterator()]

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /api/user/
       Parameters = {}
          Headers = [Accept:"application/json"]
             Body = <no character encoding set>
    Session Attrs = {}

Handler:
             Type = com.example.blog.UserController
           Method = com.example.blog.UserController#findAll()

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = org.springframework.http.converter.HttpMessageNotWritableException

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 500
    Error message = null
          Headers = [Content-Type:"application/json"]
     Content type = application/json
             Body =
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
[ERROR] Tests run: 2, Failures: 2, Errors: 0, Skipped: 0, Time elapsed: 21.598 s <<< FAILURE! - in com.example.blog.HttpControllersTests
[ERROR] List articles  Time elapsed: 0.446 s  <<< FAILURE!
java.lang.AssertionError: Status expected:<200> but was:<500>
	at com.example.blog.HttpControllersTests.List articles(HttpControllersTests.kt:30)

[ERROR] List users  Time elapsed: 0.029 s  <<< FAILURE!
java.lang.AssertionError: Status expected:<200> but was:<500>
	at com.example.blog.HttpControllersTests.List users(HttpControllersTests.kt:44)

Bắt đầu với dự án tut-spring-boot-kotlin được liên kết và chạy HttpControllersTests.kt, đặc biệt là các assertion ở dòng 30 và 44. Xem xét agent.log cùng với các lỗi của GET /api/article/ và GET /api/user/; công việc được xem là hoàn tất khi cả hai bài kiểm thử đều đạt với trạng thái 200 như mong đợi và không có lỗi serialization nào được báo cáo.