This document provides an overview and examples of testing web applications built with the Spring framework. It discusses testing Spring controllers with pure unit tests using JUnit and Mockito. It also introduces the Spring MVC test framework for server-side integration testing of Spring MVC components without requiring a running servlet container. Examples are given of testing controller methods, request mappings, exceptions, and views using the MockMvc API to build and perform mock requests and assert the response.

2. Testing Web Apps with Spring
Framework
October 18, 2014
JavaDay’14, Kyiv
Dmytro Chyzhykov

3. 3
Slides and Code Examples

4. - Build web applications with Spring Web MVC
- Familiar with mock objects unit testing (JUnit and Mockito)
4
Assumptions on Audience

5. Spring Controllers Testing
- Example Domain Model
- Subject Under Test
- Pure Unit Tests
Spring MVC Test Framework
- Standalone Server-Side Integration Tests
- Web Application Context Server-Side Integration Tests
Further materials
Q&A
5
Agenda

6. Example Domain Model
6

7. 7
Yandex.TV Service

8. 8
Domain
public class Channel {
private Integer id;
private String title;
!
// constructors, getters/setters
}

9. 9
Domain
public class Channel {
private Integer id;
private String title;
!
// constructors, getters/setters
}
DAO
@Repository
@Transactional
public interface ChannelRepository {
!
Channel findOne(Integer id);
!
}

10. Subject Under Test
10

11. 11
Subject Under Test
@Controller
@RequestMapping("/channels")
public class ChannelController {
}

12. 12
Subject Under Test
@Controller
@RequestMapping("/channels")
public class ChannelController {
@Autowired ChannelRepository channelRepository;
}

13. 13
Subject Under Test
@Controller
@RequestMapping("/channels")
public class ChannelController {
@Autowired ChannelRepository channelRepository;
!
@ResponseBody
@RequestMapping(value = "/{id}",
method = RequestMethod.GET)
public Channel getChannel(@PathVariable int id) {
// ...
}
}

14. 14
Subject Under Test
@Controller
@RequestMapping("/channels")
public class ChannelController {
@Autowired ChannelRepository channelRepository;
!
@ResponseBody
@RequestMapping(value = "/{id}",
method = RequestMethod.GET)
public Channel getChannel(@PathVariable int id) {
Channel channel = channelRepository.findOne(id);
!
if (channel != null) {
return channel;
}
!
// ...
}
}

15. 15
Subject Under Test
@Controller
@RequestMapping("/channels")
public class ChannelController {
@Autowired ChannelRepository channelRepository;
!
@ResponseBody
@RequestMapping(value = "/{id}",
method = RequestMethod.GET)
public Channel getChannel(@PathVariable int id) {
Channel channel = channelRepository.findOne(id);
!
if (channel != null) {
return channel;
}
!
throw new ChannelNotFoundException();
}
}

16. 16
Exception
@ResponseStatus(HttpStatus.NOT_FOUND)
public class ChannelNotFoundException
extends RuntimeException {
!
// constructors
!
}

17. ChannelController behaviour
- Positive test case
When we are looking for an existent channel by its id
- Negative test case
When we are looking for an absent channel by its id
17
What we are going to test

18. Pure Unit Testing
18

19. 19http://www.tubelinescaffolding.co.uk/industrial-scaffolding.htm
Scaffolding

20. 20
Unit Test Scaffolding
!
public class ChannelControllerTest {
}

21. 21
Unit Test Scaffolding
!
public class ChannelControllerTest {
@Mock
private ChannelRepository channelRepository;
}

22. 22
Unit Test Scaffolding
!
public class ChannelControllerTest {
@Mock
private ChannelRepository channelRepository;
!
@InjectMocks
private ChannelController channelController =
// optional new ChannelController();
}

23. 23
Unit Test Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerTest {
@Mock
private ChannelRepository channelRepository;
!
@InjectMocks
private ChannelController channelController =
// optional new ChannelController();
}

24. 24
Unit Test Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerTest {
@Mock
private ChannelRepository channelRepository;
!
@InjectMocks
private ChannelController channelController =
// optional new ChannelController();
!
!
@Mock
private Channel channel; // dummy
// test cases go here
}

25. 25
Positive Test Case
@Test
public void itShouldFindChannel() {
when(channelRepository.findOne(1))
.thenReturn(channel);
}

26. 26
Positive Test Case
@Test
public void itShouldFindChannel() {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
assertThat(
channelController.getChannel(1), is(channel)
);
}

27. 27
Negative Test Case
@Test
public void itShouldNotFoundChannel() {
// optional
when(channelRepository.findOne(-1))
.thenReturn(null);
}

28. 28
Negative Test Case
@Test(expected = ChannelNotFoundException.class)
public void itShouldNotFoundChannel() {
// optional
when(channelRepository.findOne(-1))
.thenReturn(null);
!
channelController.getChannel(-1);
}

29. - Easy to write
- Incredibly fast (a few milliseconds per test case)
29
Pros

30. - Can use Spring mocks from org.springframework.mock.web
- MockHttpServletRequest/Response/Session
- MockMultipartFile
- MockFilterChain
…
- ModelAndViewAssert from org.springframework.test.web
to apply asserts on a resulting ModelAndView
30
Additional Capabilities on Demand

31. - A lot left untested
- Request mappings
- Type conversion
- Transactions
- Data binding
- Validation
- Filters
- …
- No Spring annotations used
- No DispatcherServlet interactions
- No actual Spring MVC configuration loaded
31
Caveats

32. 32http://futurama.wikia.com/wiki/File:GoodNewsEveryone.jpg
Good news everyone!

33. Spring MVC Test Framework
since 3.2
33

34. <dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.1.1.RELEASE</version>
</dependency>
34
Dependency

35. 35
Server-Side Integration Testing
without a Running Servlet Container
Web
Application
Context
DispatcherServlet
Tests
Controllers
MockMvc

36. - Response status, headers, content
- Spring MVC and Servlet specific results
- Model, flash, session, request attributes
- Mapped controller method
- Resolved exceptions
- Various options for asserting the response body
- JsonPath, XPath, XMLUnit
36
What can be tested

37. - Almost all template technologies are supported
- JSON, XML, Velocity, Freemarker, Thymeleaf, PDF etc.
- Except JSP (because it relies on Servlet Container)
- you can assert only on the selected JSP view name
- No actual redirecting or forwarding
- you can assert the redirected or forwarded URL
37
Testing View Layer

38. Standalone setup for testing one individual controller at a time
without actual Spring MVC configuration loading
38
MockMvc “Standalone” Setup
private ChannelController controller = //...
!
private MockMvc mockMvc;
!
public void setUp() {
mockMvc = MockMvcBuilders.standaloneSetup(controller)
.build();
}

39. 39
MockMvc “Standalone” Setup
mockMvc = MockMvcBuilders.standaloneSetup(controller)
.setValidator(...)
.setViewResolvers(...)
.setHandlerExceptionResolvers(...)
.setMessageConverters(...)
.setLocaleResolver(...)
.addFilter(...)
//...
.build();

40. With actual Spring MVC configuration loading
40
MockMvc Web App Context Setup
// Scaffolding is omitted
!
@Autowired
private WebApplicationContext wac;
!
@Before
public void setUp() {
mockMvc = MockMvcBuilders.webAppContextSetup(wac)
.build();
}

41. 41
Creating and Performing Requests
MockHttpServletRequestBuilder request =
MockMvcRequestBuilders.get("/channels/1")
.param("foo", "bar")
.header(...)
.cookie(...)
.locale(...)
.characterEncoding("UTF-8")
.accept("application/json")
.flashAttr("flash-key", "value")
// ...
.sessionAttr("key", “value");
!
!
mockMvc.perform(request);

42. 42
Applying Asserts
mockMvc.perform(request)
.andExpect(status().isOk())
.andExpect(content().contentType("application/json"))
.andExpect(jsonPath("$.id").value(1))
// ...
.andExpect(xpath("...")...)
.andExpect(header()...)
.andExpect(cookies()...)
.andExpect(model()...)
.andExpect(view()...)
.andExpect(content()...)
.andExpect(flash()...)
.andExpect(redirectedUrl("..."));

43. 43
Resolved Exception Assert
MvcResult mvcResult = mockMvc
.perform(...)
// ...
.andReturn();
!
assertThat(
mvcResult.getResolvedException(),
instanceOf(ChannelNotFoundException.class)
);

44. - MockMvcBuilders.* to set up MockMvc instances
- MockMvcRequestBuilders.* to create requests
- MockMvcResultMatchers.* for request result assertions on
44
Useful Static Imports

45. Standalone Server-Side
Integration Tests

46. 46
Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerStandaloneIT {
@Mock
private ChannelRepository channelRepository;
@InjectMocks
private ChannelController channelController =
new ChannelController();
}

47. 47
Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerStandaloneIT {
@Mock
private ChannelRepository channelRepository;
@InjectMocks
private ChannelController channelController =
new ChannelController();
private Channel channel = new Channel(1, "MTV");
}

48. 48
Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerStandaloneIT {
@Mock
private ChannelRepository channelRepository;
@InjectMocks
private ChannelController channelController =
new ChannelController();
private Channel channel = new Channel(1, "MTV");
!
private MockMvc mockMvc;
}

49. 49
Scaffolding
@RunWith(MockitoJUnitRunner.class)
public class ChannelControllerStandaloneIT {
@Mock
private ChannelRepository channelRepository;
@InjectMocks
private ChannelController channelController =
new ChannelController();
private Channel channel = new Channel(1, "MTV");
!
private MockMvc mockMvc;
!
@Before
public void setUp() {
mockMvc = standaloneSetup(channelController)
.build();
}
// test cases go here
}

50. 50
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
}

51. 51
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
mockMvc.perform(get("/channels/1")
.accept("application/json"))
}

52. 52
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
mockMvc.perform(get("/channels/1")
.accept("application/json"))
.andExpect(status().isOk())
}

53. 53
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
mockMvc.perform(get("/channels/1")
.accept("application/json"))
.andExpect(status().isOk())
.andExpect(content()
.contentType("application/json;charset=UTF-8"))
}

54. 54
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
mockMvc.perform(get("/channels/1")
.accept("application/json"))
.andExpect(status().isOk())
.andExpect(content()
.contentType("application/json;charset=UTF-8"))
.andExpect(jsonPath("$.id").value(1))
}

55. 55
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
when(channelRepository.findOne(1))
.thenReturn(channel);
!
mockMvc.perform(get("/channels/1")
.accept("application/json"))
.andExpect(status().isOk())
.andExpect(content()
.contentType("application/json;charset=UTF-8"))
.andExpect(jsonPath("$.id").value(1))
.andExpect(jsonPath("$.title").value("MTV"));
}

56. 56
Negative Test Case
@Test
public void itShouldNotFindChannel() throws Exception {
// optional
when(channelRepository.findOne(-1)).willReturn(null);
}

57. 57
Negative Test Case
@Test
public void itShouldNotFindChannel() throws Exception {
// optional
when(channelRepository.findOne(-1)).willReturn(null);
!
mockMvc.perform(get("/channels/-1")
.accept("application/json"))
}

58. 58
Negative Test Case
@Test
public void itShouldNotFindChannel() throws Exception {
// optional
when(channelRepository.findOne(-1)).willReturn(null);
!
mockMvc.perform(get("/channels/-1")
.accept("application/json"))
.andExpect(status().isNotFound());
}

59. 59
Negative Test Case
@Test
public void itShouldNotFindChannel() throws Exception {
// optional
when(channelRepository.findOne(-1)).willReturn(null);
!
MvcResult mvcResult = mockMvc
.perform(get("/channels/-1")
.accept("application/json"))
.andExpect(status().isNotFound())
.andReturn();
!
assertThat(mvcResult.getResolvedException(),
instanceOf(ChannelNotFoundException.class));
}

60. 60
Demo

61. ChannelController instantiated
Mock of ChannelRepository injected
MockMvc was set-upped
MockHttpServletRequest prepared
Executed via DispatcherServlet
Assertions applied on the resulting MockHttpServletResponse
Assertions applied on the resulting MvcResult
61
What happened

62. - Easy to write
- Uses Spring annotations
- Always interacts with DispatcherServlet
62
Pros

63. - A bit slow (about 1 second for the first test case)
- No Actual Spring MVC configuration loaded
63
Caveats

64. Web Application Context
Server-Side Integration Tests

65. 65
Scaffolding
!
!
!
!
!
!
!
!
public class ChannelControllerWebAppIT {
}

66. 66
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
!
!
!
!
!
!
!
public class ChannelControllerWebAppIT {
}

67. 67
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
!
!
!
!
!
!
public class ChannelControllerWebAppIT {
@Autowired
private WebApplicationContext wac;
}

68. 68
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration({
"file:somewhere/servlet-context.xml",
"file:somewhere/persistence-context.xml"
})
!
!
public class ChannelControllerWebAppIT {
@Autowired
private WebApplicationContext wac;
}

69. 69
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration({
"file:somewhere/servlet-context.xml",
"file:somewhere/persistence-context.xml"
})
@Transactional
!
public class ChannelControllerWebAppIT {
@Autowired
private WebApplicationContext wac;
}

70. 70
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration({
"file:somewhere/servlet-context.xml",
"file:somewhere/persistence-context.xml"
})
@Transactional
@Sql(scripts = "classpath:test-channel-seeds.sql")
public class ChannelControllerWebAppIT {
@Autowired
private WebApplicationContext wac;
}

71. 71
Scaffolding
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration({
"file:somewhere/servlet-context.xml",
"file:somewhere/persistence-context.xml"
})
@Transactional
@Sql(scripts = "classpath:test-channel-seeds.sql")
public class ChannelControllerWebAppIT {
@Autowired
private WebApplicationContext wac;
!
private MockMvc mockMvc;
!
@Before
public void setUp() {
mockMvc = webAppContextSetup(wac).build();
}
}

72. 72
Positive Test Case
@Test
public void itShouldFindChannel() throws Exception {
mockMvc.perform(get("/channels/1")
.accept("application/json"))
.andExpect(status().isOk())
.andExpect(content()
.contentType("application/json;charset=UTF-8"))
.andExpect(jsonPath("$.id").value(1))
.andExpect(jsonPath("$.title").value("MTV"));
}

73. 73
Negative Test Case
@Test
public void itShouldNotFindChannel() throws Exception {
MvcResult mvcResult = mockMvc
.perform(get("/channels/-1")
.accept("application/json"))
.andExpect(status().isNotFound())
.andReturn();
!
assertThat(mvcResult.getResolvedException(),
instanceOf(ChannelNotFoundException.class));
}

74. 74
Demo

75. Actual Web MVC application context loaded
MockHttpServletRequest prepared
Executed via DispatcherServlet
Assertions applied on the resulting MockHttpServletResponse
Assertions applied on the resulting MvcResult
75
What happened

76. - Easy to write
- Loads actual Spring MVC configuration (cacheable)
- Uses Spring annotations
- Always Interacts with DispatcherServlet
76
Pros

77. - Slower than the “Standalone” option (depends on amount of beans
in a particular Spring Mvc configuration)
- Does not replace end-to-end testing like Selenium
77
Caveats

78. Further Materials

79. Integration between Spring MVC Test Framework and HtmlUnit.
Repository: https://github.com/spring-projects/spring-test-htmlunit
Documentation: https://github.com/spring-projects/spring-test-
htmlunit/blob/master/src/asciidoc/index.adoc
79
Spring MVC Test HtmlUnit

80. Spring Framework Reference Documentation
Chapter 11.3 Integration Testing
http://docs.spring.io/spring/docs/current/spring-framework-reference/
htmlsingle/#integration-testing
spring-test artifact source code
https://github.com/spring-projects/spring-framework/tree/master/
spring-test
Spring MVC Showcase
https://github.com/spring-projects/spring-mvc-showcase
Code examples
https://github.com/ffbit/spring-mvc-test-framework-examples
80
Links

81. Webinar: Testing Web Applications with Spring 3.2
by Sam Brannen (Swiftmind) and Rossen Stoyanchev
https://www.youtube.com/watch?v=K6x8LE7Qd1Q
Spring Testing
by Mattias Severson
https://www.youtube.com/watch?v=LYVJ69h76nw
!
81
Videos

82. Thank you!
!
Questions?

83. ffbit@yandex-team.ru
Dmytro Chyzhykov
dmytro.chyzhykov@yandex.ru
ffbit
Senior Software Engineer
at Yandex Media Services
Kyiv, Ukraine
@dcheJava

84. 84
Slides and Code Examples

85. 85http://www.dotatalk.com/wp-content/uploads/2013/09/All-hail-King-Hypno-Toad.jpg