Catching up with JUnit

It’s an unusual year for JUnit. The testing framework will see not one but three feature releases in 2025. Version 5.12 was released in February, 5.13 will be released in May, and 6.0 is scheduled for September.

First, we’ll look at JUnit 5.12, which introduced support for the new version of the Open Test Reporting XML format, including output capturing, file attachments, and a new HTML report. Contrary to the legacy XML format, Open Test Reporting supports all features of the JUnit Platform. Moreover, adoption by other ecosystems has already started.

Next, we’ll cover JUnit 5.13, which added support for parameterizing test classes rather than just methods. Parameterized classes were the most highly voted issue in JUnit’s issue tracker. Besides unlocking new use cases, they finally offer a straightforward migration path from JUnit 4 parameterized tests.

Last but not least, we’ll share our plans for JUnit 6.0 which, among other things, will raise the Java and Kotlin baselines to 17 and 2.x, respectively.

Transcript

1. Catching up with JUnit 5.12, 5.13, and beyond 1
2. Marc Philipp 2
3. JUnit in a nutshell • • • • • 3
4. Thank you to our sponsors! 4
5. The Sovereign Tech Fund is investing in JUnit in 2024 and 2025! 5
6. Sovereign Tech Fund • • 6
7. JUnit Generations 7
8. JUnit Generations 7.1
9. JUnit Generations 7.2
10. JUnit Generations 7.3
11. Full-time work on JUnit (2024-2025) 8
12. Full-time work on JUnit (2024-2025) • 8.1
13. Full-time work on JUnit (2024-2025) • • 8.2
14. Full-time work on JUnit (2024-2025) • • • 8.3
15. Full-time work on JUnit (2024-2025) • • • • 8.4
16. Full-time work on JUnit (2024-2025) • • • • • 8.5
17. Full-time work on JUnit (2024-2025) • • • • • • 8.6
18. Full-time work on JUnit (2024-2025) • • • • • • • 8.7
19. Full-time work on JUnit (2024-2025) • • • • • • • • 8.8
20. Full-time work on JUnit (2024-2025) • • • • • • • • 8.9
21. Today’s Agenda 9
22. Better Test Reports 10
23. Open Test Reporting XML format • • junit-platform- reporting • junit.platform.reporting.open.xml.enabled=true 11
24. Event-based format <?xml version="1.0" ?> <e:events xmlns="https:��schemas.opentest4j.org/reporting/core/0.1.0" xmlns:e="https:��schemas.opentest4j.o <infrastructure><hostName>�����hostName><userName>marc��userName><operatingSystem>Mac OS X��operatingSystem <e:started id="766" name="JUnit Jupiter" time="2022-09-23T07:54:50.324086Z"><metadata><junit:uniqueId <e:started id="767" name="ColorPaletteTests" parentId="766" time="2022-09-23T07:54:50.324275Z"><metadata <e:started id="768" name="DemonstratePalettesTests" parentId="767" time="2022-09-23T07:54:50.324456Z" <e:started id="769" name="flat_default()" parentId="768" time="2022-09-23T07:54:50.324589Z"><metadata <e:finished id="769" time="2022-09-23T07:54:50.326039Z"><result status="SUCCESSFUL">��result>��e:finished <e:finished id="768" time="2022-09-23T07:54:50.332254Z"><result status="SUCCESSFUL">��result>��e:finished <e:finished id="767" time="2022-09-23T07:54:50.333862Z"><result status="SUCCESSFUL">��result>��e:finished <e:finished id="766" time="2022-09-23T07:54:50.812066Z"><result status="SUCCESSFUL">��result>��e:finished ��e:events> 12
25. Hierarchical format <?xml version="1.0" encoding="UTF-8" standalone="no"?> <h:execution xmlns:h="https:��schemas.opentest4j.org/reporting/hierarchy/0.1.0" xmlns="https:��schemas.open <infrastructure>���� ��� �����infrastructure> <h:root duration="PT0.48798S" name="JUnit Jupiter" start="2022-09-23T07:54:50.324086Z"> <metadata> <junit:uniqueId>[engine:junit-jupiter]��junit:uniqueId> <junit:legacyReportingName>JUnit Jupiter��junit:legacyReportingName> <junit:type>CONTAINER��junit:type> ��metadata> <result status="SUCCESSFUL"�� <h:child duration="PT0.009587S" name="ColorPaletteTests" start="2022-09-23T07:54:50.324275Z"> <metadata>���� ��� �����metadata> <sources><java:classSource className="org.junit.platform.console.tasks.ColorPaletteTests"���� <result status="SUCCESSFUL"�� <h:child duration="PT0.007798S" name="DemonstratePalettesTests" start="2022-09-23T07:54:50.324456Z" <metadata>���� ��� �����metadata> <sources><java:classSource className="org.junit.platform.console.tasks.ColorPaletteTests$Demonstrat <result status="SUCCESSFUL"�� <h:child duration="PT0.00145S" name="flat_default()" start="2022-09-23T07:54:50.324589Z"> <metadata>���� ��� �����metadata> <sources><java:methodSource className="org.junit.platform.console.tasks.ColorPaletteTests$Demonst <result status="SUCCESSFUL"�� ��h:child> ��h:child> 13
26. HTML Report • ▪ • 14
27. Demo 15
28. Platform-agnostic and extensible • • 16
29. Future work • • • 17
30. Parameterized Test Classes 18
31. Parameterized Test Methods • @ParameterizedTest • @���Source class SomeTests { @ParameterizedTest @ValueSource(strings = {"foo", "bar"}) void shouldNotBeNull(String value) { assertNotNull(value); } @ParameterizedTest @ValueSource(strings = {"foo", "bar"}) void lengthShouldBeThree() { assertEquals(3, value.length()); } } 19
32. Parameterized Test Classes • @ParameterizedClass • @���Source @ParameterizedClass @ValueSource(strings = { "foo", "bar"}) class SomeTests { @Parameter String value; @Test void shouldNotBeNull() { assertNotNull(value); } @Test void lengthShouldBeThree() { assertEquals(3, value.length()); } } 20
33. Consuming Arguments • • @ParameterizedClass @ValueSource(strings = { "foo", "bar"}) record SomeTests(String value) { @Test void shouldNotBeNull() { assertNotNull(value); } @Test void lengthShouldBeThree() { assertEquals(3, value.length()); } } 21
34. Demo 22
35. Mutable vs. immutable arguments • @ParameterizedClass • • @AfterEach 23
36. Argument Source Annotations • @ValueSource @EnumSource @NullSource @EmptySource • @CsvSource @CsvFileSource • @MethodSource @FieldSource • @ArgumentsSource(MyProvider.class) 24
37. Lifecycle Methods (Recap) • @BeforeParameterizedClassInvocation @AfterParameterizedClassInvocation • 25
38. Discovery Issues 26
39. Discovery issues? 27
40. Valid test methods? @Test �� Java int test() { return 42; } @Test �� Kotlin fun test(): Nothing = fail() 28
41. Valid test methods? @Test �� Java int test() { return 42; } @Test �� Kotlin fun test(): Nothing = fail() @Test void Unit 28.1
42. Malformed declarations • • • 29
43. Discovery issue reporting • • • • junit.platform.discovery.issue.severity.critical 30
44. Demo 31
45. Roadmap for 6.0 32
46. Overview of 6.0 • ▪ ▪ • 33
47. Major changes in 6.0 34
48. Major changes in 6.0 • 34.1
49. Major changes in 6.0 • • 34.2
50. Major changes in 6.0 • • • @Nullable 34.3
51. Major changes in 6.0 • • • @Nullable • 34.4
52. Major changes in 6.0 • • • @Nullable • ▪ 34.5
53. Major changes in 6.0 • • • @Nullable • ▪ • 34.6
54. Long(er)-Term Support for 5.13.x • • 35
55. Timeline for 6.0 36
56. Timeline for 6.0 36.1
57. Timeline for 6.0 ⋮ 36.2
58. Timeline for 6.0 ⋮ ⋮ 36.3
59. Spring Framework 7.0 will be based on JUnit 6.0 37
60. We need your help! 38
61. Did I mention we need a new logo? 39
62. Example Code and Slides • • 40
63. Q & A 41
64. Thanks! 42