JUnit. New Opportunities for Testing on the

Transcription

1 JUnit New Opportunities for Testing on the JVM

2 Sam Brannen Spring and Java Consultant Trainer, Coach, Hardcore developer at heart Java Developer for about 20 years Spring Framework Core Committer since 2007 JUnit 5 Core Committer since October 2015

3 Experts in Spring and Enterprise Java Areas of expertise Spring * JUnit 5 Java EE Software Architecture Code Reviews Where you find us Zurich,

4 Agenda Impetus for Change JUnit 5 Spring 5 Q & A

5 Show of hands

6 Why a new version of JUnit?

7 Impetus for Change JUnit 4.0 was released a decade ago a lot has changed since then testing needs have matured expectations have grown Modularity à big ball of mud (i.e., only THE junit.jar) Test discovery and execution à tightly coupled Extensibility à lot of room for improvement Let s not forget Java 8 and Java 9

8 JUnit 4 Runner API Very powerful In fact, it can do anything But you can t combine Runners Parameterized + SpringRunner à no way

9 JUnit 4 Rules are meant to be broken JUnit 4.7: MethodRule JUnit 4.9: TestRule Great for simple use cases Can even be combined But a single rule can t be used for method-level and class-level callbacks Plus zero support for instance-level callbacks Case in point: SpringClassRule / SpringMethodRule

10 JUnit Lambda Crowdfunding Campaign Initiated by Johannes Link and Marc Philipp Later joined by Matthias Merdes, Stefan Bechtold, & Sam Brannen Ran from July to October 2015 Raised 53,937 Euros from 474 individuals and companies 4 companies donated 6 weeks of developer time

11 Thanks!

12 The Kick-off Team

13 JUnit 5

14 Roadmap Prototype à December 2 nd, ALPHA à February 1 st, Milestones à July 2016 July Release Candidates à July 2017 August GA à September 10 th, à Today! (October 3 rd, 2017)

15 JUnit 5 in a Nutshell Modular Extensible Modern Forward and backward compatible JUnit Platform supports JUnit 3.8, JUnit 4, and JUnit 5 New testing frameworks can be run with JUnit 4 infrastructure

16 JUnit 5 Java Versions Java 8 baseline but can be used to test application code compiled against previous JDK versions Java 9 #WorksFineOnJDK9 every artifact has a stable AUTOMATIC-MODULE-NAME module-path scanning support coming in 5.1

17 JUnit 5 = Platform + Jupiter + Vintage JUnit Platform Foundation for launching testing frameworks on the JVM Launcher and TestEngine APIs Revolutionary ConsoleLauncher, Gradle plugin, Maven Surefire provider JUnit Jupiter New programming model and extension model for JUnit 5 Evolutionary JUnit Vintage TestEngine for running JUnit 3 and JUnit 4 based tests Necessary

18 Launcher API Used by IDEs and build tools to launch the framework Central API for discovering and executing tests via one or more engines LauncherDiscoveryRequest selectors and filters Feedback provided via the TestExecutionListener API ConsoleLauncher for command-line support

19 TestEngine API Test engine discovers and executes tests for a particular programming model Automatic registration via Java s ServiceLoader mechanism JupiterTestEngine VintageTestEngine Implement your own

20 Third-party TestEngines Specsy Spek Cucumber Drools Scenario jqwik source:

21 VINTAGE JUPITER THIRD PARTY PLATFORM

22 THIRD PARTY JUPITER VINTAGE PLATFORM

23 IDEs and Build Tools IntelliJ: IDEA Eclipse: NetBeans: Eclipse Oxygen 4.7.1a (to be released next week) Gradle: interim solution from JUnit Team to be taken over by Gradle team (end of 2017) Android JUnit 5: third-party Android support Maven: interim solution from JUnit Team being taken over by Maven Surefire team See user guide and sample apps for examples

24 JUnit Jupiter Extension Model Extension marker interface org.junit.jupiter.api.extension package containing all extension APIs implement as many as you used to register one or more extensions interface, class, or method level o or as a meta-annotation

25 Extension APIs BeforeAllCallback BeforeEachCallback BeforeTestExecutionCallback AfterTestExecutionCallback AfterEachCallback AfterAllCallback Lifecycle Callbacks TestExecutionExceptionHandler ExecutionCondition TestInstancePostProcessor ParameterResolver TestTemplateInvocationContextProvider Dependency Injection

26 JUnit Jupiter Programming Model org.junit.jupiter.api (org.junit.jupiter.params) Annotations and meta-annotations Assertions and Assumptions Custom display names Visibility Tagging Conditional test execution Dependency injection for constructors and methods Lambda expressions and method references Interface default methods Nested test classes Repeated tests, parameterized tests, dynamic tests

27 for TestEngine @Nested / @Disabled

28 JUnit 4 Rule Migration o located in experimental junit-jupiter-migrationsupport module o registers 3 extensions for JUnit Jupiter ExternalResourceSupport o TemporaryFolder, etc. VerifierSupport o ErrorCollector, etc. ExpectedExceptionSupport o ExpectedException o minor bug in 5.0.0; fixed in 5.0.1

29 Assertions org.junit.jupiter.api.assertions Limited set of core assertions assertequals(), assertnotnull(), etc. assertthrows() λ asserttimeout() and asserttimeoutpreemptively() λ assertall() λ Supplier<String> à λ for lazy failure message evaluation message is now the last parameter For more power, use AssertJ, Hamcrest, etc.

30 Assumptions org.junit.jupiter.api.assumptions Limited set of core assumptions For aborting tests mid-flight Otherwise, favor a custom ExecutionCondition for skipping assumetrue() / assumefalse() BooleanSupplier, Supplier<String> λ assumingthat(?, () -> {} ); λ

31 LIVE CODING DEMO from JUnit 4 to JUnit Jupiter

32 Tagging on a test interface, class, void myfasttest() { }

33 Custom Tags as @Tag("fast") Fast void myfasttest() {}

34 Composed Tags as a meta-annotation with other annotations (JUnit, FastTest { void myfasttest() { }

35 Test Names Names default to test class or test method names characters limited based on Java syntax Custom display names Can contain spaces, special chars, and even emoji

36 Dependency Injection Extension Model meets Programming Model ParameterResolver extension API resolves parameters for constructors or method o not and lifecycle methods can register multiple simultaneously only one wins Use cases server URL, DataSource, Spring ApplicationContext, etc.

37 TestInfo TestInfo: inject etc. access display name, tags, class, method TestInfoParameterResolver eating our own dog food ;-) See also: RepetitionInfo TestReporter MockitoExtension SpringExtension

38 LIVE CODING DEMO tags, display names, and dependency injection

39 Conditional Test Execution Extension Model meets Programming Model DisabledCondition Game Changer eating our own dog food ;-) Deactivate via Launcher, system property, or junit-platform.properties file junit.conditions.deactivate = org.junit.*

40 Interface Default Methods Introduces the concept of a test interface Enables multiple inheritance in tests a.k.a., testing @Test See StringTests and TestInterfaceDemo examples in user guide

41 DEMO default methods

42 Nested Test Classes Enables logical, hierarchical grouping of test classes with shared initialization and state from outer classes on non-static nested classes i.e., inner classes You can even combine nested classes and test interfaces See TestingAStack example in user guide and Bowling Game Kata by Tim Riemer

43 DEMO nested test classes

44 Repeated Tests Annotate a method instead o and specify the number of repetitions Optionally have the RepetitionInfo injected as a method parameter Optionally override the display name

45 @RepeatedTest in void repeatedtest(repetitioninfo repetitioninfo) { assertequals(5, repetitioninfo.gettotalrepetitions()); value = 5, name = "Wiederholung {currentrepetition} von {totalrepetitions} ) void repeatedtestingerman() { //... }

46 Parameterized Tests (junit-jupiter-params) Annotate a method instead o and specify the source of the arguments o optionally override the display name Sources String, int, long, double & custom ArgumentsProvider

47 Argument Conversion Implicit conversion o Primitive types and their wrappers o Enums o java.time types (JSR-310) Explicit conversion and custom ArgumentConverter built-in support for JSR-310

48 @ParameterizedTest = { "mom", "dad", "radar", "racecar", "able was I ere I saw elba" }) void palindromes(string candidate) { asserttrue(ispalindrome(candidate)); }

49 LIVE CODING DEMO repeated and parameterized tests

50 Dynamic Tests Conventional tests are static (i.e., known at compile A DynamicTest is registered at runtime λ as lambda expression in a stream, collection, etc. by a method annotated Can also register a DynamicContainer for dynamic nesting Somewhat analogous to parameterized tests just more dynamic

51 Dynamic Tests in Stream<DynamicTest> dynamictestsfromintstream() { // Generates tests for the first 10 even integers. return IntStream.iterate(0, n -> n + 2).limit(10).mapToObj(n -> dynamictest("test" + n, () -> asserttrue(n % 2 == 0))); }

52 DEMO dynamic tests

53 What s Missing? Scenario tests Ordering Parallel execution Execution in user-defined thread Declarative test suites for the JUnit Platform Java 9 module-path scanning

54 Spring 5 + JUnit 5

55 Spring Support for JUnit Jupiter Fully integrated in Spring Framework 5.0! released last week Supports all Core Spring TestContext Framework features Constructor and method @Value Conditional test execution via SpEL expressions ApplicationContext configuration annotations Also works with Spring Framework 4.3

56 Configuring JUnit Jupiter with @ContextConfiguration @EnabledIf SpEL expression evaluation for conditional execution

57 DEMO Spring 5 and JUnit

58 Spring Boot JUnit 5 Custom SpringEventsWebTest { }

59 Spring Boot JUnit 5 MockMvc + method-level DI + class EventsControllerTests page should display more than 10 events") void listevents(@autowired MockMvc mockmvc) throws Exception { mockmvc.perform(get("/")).andexpect(view().name("event/list")).andexpect(model().attribute("events", hassize(greaterthan(10)))); }

60 In closing

61 JUnit 5 Resources Project Homepage à User Guide à Javadoc à GitHub à Gitter à Stack Overflow à

62 Spring Resources Spring Framework à Spring Guides à Spring JIRA à Spring on GitHub à Stack Overflow à spring, spring-test, spring-mvc, spring-boot,

63 Additional JUnit 5 JavaOne 2017 JUnit 5 BOF Tuesday, Oct 03, 6:45 p.m. - 7:30 p.m. Moscone West - Room 2016 JUnit5: Features, Architecture, and Extensibility Wednesday, Oct 04, 2:45 p.m. - 3:30 p.m. Moscone West - Room 2009

64 Demos Used in this Presentation

65 JUnit Q & A Sam Brannen