Coding Capital Markets

Speaker: Sam Brannen
Twitter: @sam_brannen

Agenda

• Spring Events App
• Spring 4.3
• JUnit 5
• Spring 5

Spring Events App

The Spring Events App is a Spring boot powered web app using
Spring Boot 1.4, Spring Framework 5, JUnit 5.

• Simple PJO Domain model: Event
• Transactional service layer
• Spring Data JPA
• Spring MV
• github.com/sbrannen/spring-events

Odds & Ends

• JUnit 4.12+ required by the Spring TestContext framework (TCF)
• Support for Primary transaction managers and data sources in TCF
• @Sql and @Sqlgroup many now be used as meta-annotations:
  • to create custom composed annotations with attribute overrides
  • Same is true for many @Repeatable annotations in Core Spring
• ReflectionTestUtils automatically unwraps proxies when setting/getting a field

Extending the Spring TextContext Framework

• The getTestContext() method in TestContextManager is now public
• New ContextCustomizer and ContextCustomizerFactory SPIs
  • Potentially replaces need for custom ContextLoader
  • Customize ApplicationContext after bean definitions are loaded but before context is refreshed
  • Registered globally by third parties via spring.factories mechanism
  • Enables Spring Boot Test Magic

New Features

• SpringRunner alias for the SpringJUnit4ClassRunner
  >> @RunWith(SpringRunner.class)
• @ContextConfiguration can be completely omitted…
  • if default XML or @Configuration is detected
  • Spring Boot test 1.4 even locates your @SpringBootApplication class
• ApplicationContext cache is now bounded

Preparing for the Future

• Testing Traits
  • Spring test annotations can be declared on interfaces
  • Combines nicely with Java 8 default methods and JUnit 5
• Non-public @Transactional test methods: for use with JUnit 5 and TestNG
• Non-public @BeforeTransaction and @AfterTransaction methods

MockMvc Improvements

• Expectations on multi-value response headers: HeaderResultMatchers.stringValues(…)
• Form data equest content (e.g., from a POST) now parsed and used to populate request params
• Support for Custom HTTP verbs (e.g. WebDAV)
• Improve Cookie support for HtmlUnit integration

MockMvc – Assert invoked Handler Method

New mock-like methodCall() assertion in HandlerResultMatchers: Assert the @Controller method invoked to handle the response:

    mockMvc.perform(get("/"))
    .andExpect(handler().methodCall(
     on(HomeController.class).showHomePage()));

MockMvc – JSON Prefixes

New support for stripping JSON prefixes from Responses. A prefix is used to prohibit JSON hijacking:

    mockMvc.perform(get("/account/42").accept(APPLICATION_JSON))
    .andExpect(jsonPath("$.pin")
    .prefix("&&enigma&&")
    ...

MockRestServiceServer Improvements

• Expectations for form data in the request body
• Specify expectation counts
  • Pass ExpectedCount to the expect() method
  • once(), manyTimes(), times(int), min(int), max(int), between(int, int)
  • verify() and reset() afterwards
• Specify whether ordering should be ignored: invoke ignoreExpectOrder(true) on the MockResetServiceServerBuilder

JUnit 5: Impetus for Change

• JUnit 4.0 was released a decade ago
• Modularity -> big ball of mud (i.e., only THE junit.jar)
• Test Discovery and execution -> tightly coupled
• Extensibility -> lot of room for improvement
• Java 8 support

JUnit 4 Runner API

• Very Powerful
• You can do anything
• But you cannot combine Runners
• Parameterized + SpringJUnit4ClassRunner -> no way

JUnit 4… Rules… are meant to be broken

• JUnit 4.7: MethodRule -> @Rule
• JUnit 4.9: TestRule -> @Rule/@ClassRule

JUnit Lambda

• Initiated by Johannes Link and Marc Philipp
• Later joined by Matthias Merdes, Stefan Bechtold, and Sam Brannen

JUnit 5 – Roadmap

• Prototype – December 2015
• Alpha – February 2016
• M1 & M2 – July 2016
• M3, M4, RC1 – Fall 2016
• GA – End of 2016… maybe

JUnit 5 – In a Nutshell

• Modular
• Extensible
• Modern
• Forward & Backward Compatible
  • JUnit Platform supports JUnit 3.8, 4 and 5
  • New testing frameworks can be run with JUnit 4 infrastructure:
    @RunWith(JUnitPlatform.class)

JUnit 5 = Platform + Jupiter + Vintage

• JUnit Platform 1.0.0
  • Foundation for launching testing frameworks on the JVM
  • Launcher and TestEngine APIs
  • ConsoleLauncher, Gradle Plugin, Maven Surefire provider
• JUnit Jupiter 5.0.0: New programming model and extension model for JUnit 5
• JUnit Vintage 4.12.0: TestEngine for running old stuff

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

TestEngine API

• aka, Runner in JUnit 4
• Test engine discovers and executes tests for a particular programming model
• Automatic registration via Java’s ServiceLoader mechanism
• JupiterTestEngine
• VintageTestEngine
• Implement your own…

Extension APIs

• BeforeAllCallback
• BeforeEachCallback
• BeforeTestExecutionCallback
• AfterTestExecutionCallback
• AfterEachCallback
• AfterAllCallback
• ContainerExecutionCondition & TestExecutionCondition
• TestInstancePostProcessor
• ParameterResolver
• TestExecutionExceptionHandler

JUnit 5 – Programming Model

org.junit.jupiter.api

• Annotations & Meta-annotations
• Assertions & Assumptions
• Custom Display Names
• Visibility
• Tagging
• Conditional Test Execution
• DI for Constructors and methods
• Lambda Expressions and method references
• Interface default methods
• Nested test classes
• Dynamic Tests

Annotations

• @Test / @TestFactory
• @BeforeAll / @AfterAll
• @BeforeEach / @AfterEach
• @DisplayName
• @Tag
• @Disabled
• @Nested

Assertions

org.junit.jupiter.api.Assertions

• Limited set of core assertions
• assertThrows() and expectThrows()
• assertTimeout()
• assertAll()