JUnit 5
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The document discusses JUnit 5, a testing platform for the JVM that operates alongside JUnit 3 and 4, highlighting its important new features and IDE support. It explains the separation of JUnit 5 into modular components: JUnit Platform, JUnit Jupiter, and JUnit Vintage, and provides examples of the new testing capabilities and extensions. The content emphasizes JUnit 5's flexibility with various testing implementations and its enhanced support for modern testing frameworks.
![kgolev.com@kotseto
4.11:
org.junit.ComparisonFailure:
expected:<[1]L> but was:<[2]L>
assertEquals(1, 2)](https://image.slidesharecdn.com/junit5-2018-180329152027/85/JUnit-5-9-320.jpg)
JUnit 5
- 1. kgolev.com@kotseto JUnit 5 Kostadin Golev CTO @ Rewards Labs The Next Generation
- 3. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 7. kgolev.com@kotseto How bad? Let’s rename some private variables to find out!
- 9. kgolev.com@kotseto 4.11: org.junit.ComparisonFailure: expected:<[1]L> but was:<[2]L> assertEquals(1, 2)
- 10. kgolev.com@kotseto 4.12-beta-1: org.junit.ComparisonFailure: expected: null<null> but was: null<null> assertEquals(1, 2)
- 11. kgolev.com@kotseto Extension mechanism Runner @RunWith(SpringJUnit4ClassRunner.class) Rule @Rule ExpectedException thrown = none()
- 15. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 17. kgolev.com@kotseto There is no single JUnit 5 (JAR)
- 18. kgolev.com@kotseto Not one big fat jar We have more then ten now, in three groups
- 19. kgolev.com@kotseto JUnit Platform + JUnit Jupiter + JUnit Vintage JUnit 5
- 22. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 28. kgolev.com@kotseto @Test void exception() { RuntimeException thrown = assertThrows(RuntimeException.class, () -> library.throwRuntimeException("message") ); assertEquals("message", thrown.getMessage()); }
- 31. kgolev.com@kotseto What about Runners and Rules?
- 32. kgolev.com@kotseto We wrote some tests! How do we run them?
- 33. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 34. kgolev.com@kotseto Some History Or how JUnit 5 team discovered they were building a platform
- 35. kgolev.com@kotseto It started as a big fat jar Then everything got split in small, focused modules
- 36. kgolev.com@kotseto Launcher <<interface>> Engine Engine Impl Jupiter API implements JUnit Platform JUnit Jupiter
- 38. kgolev.com@kotseto <<interface>> Engine Engine Implementation implements JUnit Platform JUnit Jupiter
- 41. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3&4 Important New Features IDE & Tool Support
- 42. kgolev.com@kotseto You can still run your JUnit 3&4 tests But it will not be JUnit 3&4 running them
- 43. kgolev.com@kotseto Launcher <<interface>> Engine Vintage Engine Impl JUnit 3&4 API implements JUnit Platform JUnit Vintage
- 44. kgolev.com@kotseto JUnit Platform JUnit Jupiter JUnit Vintage JUnit5 tests JUnit4 tests
- 46. kgolev.com@kotseto Platform for the JVM Many Developers implemented their own engines, reusing JUnit5 tool integration
- 47. kgolev.com@kotseto Not only for Java Test Engine implementations exist for Scala, Kotlin and Groovy
- 48. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 50. kgolev.com@kotseto assertEquals(1, 2); assertEquals("String", "Another String"); org.opentest4j.AssertionFailedError: Expected :1 Actual :2
- 51. kgolev.com@kotseto assertAll( () -> assertEquals(1, 2), () -> assertEquals("String", “Another String") ) org.opentest4j.MultipleFailuresError: Multiple Failures (2 failures) expected: <1> but was: <2> expected: <String> but was: <Another String>
- 52. kgolev.com@kotseto What about Runners and Rules (again)? JUnit5 Extension model
- 55. kgolev.com@kotseto Composable & Powerful Use as many as you want whenever you want them
- 56. kgolev.com@kotseto @ExtendWith(SpringExtension.class) @ExtendWith(MockitoExtension.class) class SpringTest { @Autowired SpringComponent component; @Mock Dependency mocked;
- 57. kgolev.com@kotseto class ParameterInTestMethods { @Test @ExtendWith(MockitoExtension.class) void test(@Mock Dependency mocked) { … }
- 59. kgolev.com@kotseto public class MockitoExtension implements TestInstancePostProcessor { @Override public void postProcessTestInstance( Object testInstance, ExtensionContext context) { MockitoAnnotations.initMocks(testInstance); } }
- 60. kgolev.com@kotseto Some official extensions SpringExtension - since Spring 5.0 (Sep 2017) MockitoExtension - since 2.17.0 (Mar 2018)
- 62. kgolev.com@kotseto public class Library { private Books books; public Library(Books books) { this.books = books; } public void addBook(Book book) { // do something with books } }
- 63. kgolev.com@kotseto @Test void whenBookExistsThenIncrementAmount() {} @Test void whenBookExistsThenCheckAmountMoreThenN() {} @Test void whenBookDoesNotExistThenCreateBook() {} @Test void whenBookDoesNotExistThenSendNewBookNotification() {}
- 67. kgolev.com@kotseto Tests are often a tree, not a list
- 69. kgolev.com@kotseto @DisplayName("Book is added to library") class BookAddedTest { @DisplayName("when book exists") @Nested class whenBookExists { @DisplayName("amount++") @Test void incrementAmount() {} @DisplayName("check amount > limit") @Test void checkAmountMoreThenLimit() {} } . . . }
- 73. kgolev.com@kotseto @Test void strIsLessThenTenChar() { int value = "str".length(); assertTrue(value < 10); } @Test void StringIsLessThenTenChar() { int value = "String".length(); assertTrue(value < 10); }
- 77. kgolev.com@kotseto @ValueSource(strings = {“str”, “String”}) @ValueSource(ints = {1, 3, 7, 9}) @EnumSource(SomeEnum.class) @CsvSource({"1, 1", "2, 4", "4, 16”}) @CsvFileSource(resources=“testData.csv”)
- 78. kgolev.com@kotseto @MethodSource(names=“stringAndIntProvider") … static Stream<Arguments> stringAndIntProvider() { return Stream.of( ObjectArrayArguments.create("foo", 3), ObjectArrayArguments.create("foobar", 6) ); }
- 79. kgolev.com@kotseto enum Status { OK, INVALID_NAME, INVALID_DATE, … } @ParameterizedTest @EnumSource(value = Status.class, mode = EXCLUDE, names = “OK") void should_return_error_when_not_OK(Status status) { …
- 81. kgolev.com@kotseto Why JUnit 5? Where Is It? Writing Tests Platform For The JVM Running Along JUnit 3 & 4 Important New Features IDE & Tool Support
- 82. kgolev.com@kotseto Also supported pre-GA releases Since Oxygen 4.7.1
- 83. kgolev.com@kotseto Surefire provider Not native yet Native support since 4.6 Plugin
- 84. kgolev.com@kotseto testCompile "org.junit.jupiter:junit-jupiter-api:5.0.0" testRuntime "org.junit.jupiter:junit-jupiter-engine:5.0.0" testCompile "org.junit.jupiter:junit-jupiter-params:5.0.0" … test { useJUnitPlatform { includeEngines 'junit-jupiter', 'junit-vintage' } failFast = true }