JUnit 5 - RainFocus · Junit 5: Features, Architecture, and Extensibility - JUnit 5 Steve Moyer Steve Seltzer Niraja Ramesh The Pennsylvania State University

Junit 5: Features, Architecture, and Extensibility - http://bit.ly/psu-junit5-j1

JUnit 5

Steve MoyerSteve Seltzer

Niraja Ramesh

The Pennsylvania State University

Features, Architecture, and Extensibility


About Us

● Steve Moyer– Enterprise Architect

● Steve Seltzer– Programmer/Analyst

● Niraja Ramesh– Programmer/Analyst


About Us● Enterprise Infrastructure and Operations

● Core IT support organization for Penn State

● Software Engineering Unit


Agenda

● Rationale● Architecture● Principles● Features● Code examples● Future directions ● References


Rationale

● Decouple test execution and reporting from test definition and provisioning

● Rethinking the JUnit’s extensibility story● Support for Java 8 features (Lambdas, Streams,

Interface default methods) for better assertions, generating test cases, formulating test hierachies, testing asynchronous code and other stuff


Architecture


Architecture


What do I need?

● junit-jupiter-api – to compile test classes and/or extensions

● junit-jupiter-engine (and dependencies) – to run JUnit 5 tests

● junit-vintage-engine (and dependencies) – to run JUnit 4 tests (using JUnit 5)


What do I need?

● junit-platform-console (and dependencies) – to execute JUnit 5 tests from the command line

● junit-platform-runner (and dependencies) – to execute JUnit 5 tests using JUnit 4

– provides a way to run JUnit 5 tests in Eclipse and (some) other tools that don’t yet natively support JUnit 5.


What do I need?

● junit-platform-maven-provider – to execute tests using JUnit 5 during a Maven build.

– See the Maven example at: https://github.com/junit-team/junit5-samples/tree/master/junit5-maven-consumer

● junit-platform-gradle-plugin – to execute tests using JUnit 5 during a Gradle build.

– See the Gradle example at: https://github.com/junit-team/junit5-samples/tree/master/junit5-gradle-consumer

https://github.com/junit-team/junit5-samples/tree/master/junit5-maven-consumer

https://github.com/junit-team/junit5-samples/tree/master/junit5-gradle-consumer


Set upplugin

https://github.com/PennState/junit5-presentation/blob/master/pom.xml

https://github.com/PennState/junit5-presentation/blob/master/pom.xml


Set updependencies


Principles


Principles

● Prefer extension points over features● An extension point should be good at one thing● It should be hard to write tests that behave

differently based on how they are run● Tests should be easy to understand● Minimize dependencies (especially third-party)

https://github.com/junit-team/junit5/wiki/Core-Principles

https://github.com/junit-team/junit5/wiki/Core-Principles


Features


Features

● Meta-Annotations ● Tags and filters● Dependency injection through parameters

on constructors and methods● Interface default methods● Dynamic tests (runtime)● Extensions


Features● API Isolation

– Jupiter API for writing tests and extensions

– Engine API for writing new engines

● API Evolution– API annotations

● Internal ● Deprecated● Experimental ● Maintained ● Stable


Code Examples


Code Examples● Assertion tests● Exception tests● Assumption tests● Meta-Annotation● Dynamic tests● Extension tests● Grouped tests● Nested tests


Assertions


Assertion TestsSimple Assertions

Junit 4 Junit 5

assert...(expected, actual) assert...(expected, actual)

assert...(message, expected, actual) assert...(expected, actual, message)


Assertion TestsSimple Assertions


Assertion Tests


Assertion Tests

AssertionTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/AssertionTests.java


Maven Output

output - txt file

output - xml file

maven console output


Available Assertions

http://junit.org/junit5/docs/current/api/org/junit/jupiter/api/Assertions.html

● assertTrue

● assertFalse

● assertEquals

● assertNotEquals

● assertArrayEquals

● fail

● assertNull

● assertNotNull

● assertSame

● assertNotSame

● assertAll

● assertThrows

● expectThrows

http://junit.org/junit5/docs/current/api/org/junit/jupiter/api/Assertions.html


Exception Tests

ExceptionTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/ExceptionTests.java


Exception Tests

SampleStudents.java

The class builds data models for freshman, part-time, full-time and so forth.

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/supportingcode/SampleStudents.java


Exception Tests

BuildTestCourses.java

This class creates different courses that we will register the students throughout our tests.

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/supportingcode/BuildTestCourses.java


Exception Tests

CourseUtils.java

This class registers courses for the students.Throws exception if their total credits exceed MAX_ALLOWED.

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/supportingcode/CourseUtils.java


Exception Tests

Total credits for all courses exceed 25‘registerForCourse’ method throws an exception

assertThrows compares the thrown exception class to the expected one

ExceptionTests.java



Exception Tests

ExceptionTests.java



Assumptions


Assumptions Tests

● assumeTrue● assumeFalse● assumingThat


Assumption TestsassumeTrue

AssumptionTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/AssumptionTests.java


Assumptions Test


assumeFalse



Assumptions TestassumingThat




Meta-Annotations


Meta-Annotation

UseridCaseTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/UseridCaseTests.java


Tagging & Filtering

TaggingTest.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/TaggingTest.java


Dynamic Tests


Dynamic Test

● Test case generated at run-time by a factory method @TestFactory

● Composed of a display name and an Executable● Executable is a functional interface – meaning tests

can be provided as lambda expressions or method references

● Because of dynamic nature, lifecycle callbacks are not applicable


Dynamic Testing

DynamicTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/DynamicTests.java


Extensibility


Extension Points

● ParameterResolver● ContainerExecutionCondition● TestExecutionCondition● TestInstancePostProcessor

● BeforeAllCallback● AfterAllCallback● BeforeEachCallback● AfterEachCallback● BeforeTestExecutionCallback● AfterTestExecutionCallback

http://junit.org/junit5/docs/current/api/org/junit/jupiter/api/extension/Extension.html

http://junit.org/junit5/docs/current/api/org/junit/jupiter/api/extension/Extension.html


Extension PointTestExecutionCondition


Extension Test

This class disables a test if the method name does not contain the word ‘affiliate’

AfflliateDetector.java

implements TestExecutionCondition

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/AfflliateDetector.java


Extension Test

Class ExtensionDisabledTests contains a method that will return a boolean indicating whether method name contains the word ‘student’

Register AffiliateDetector extension via @ExtendWith

ExtensionDisabledTests.java

implements TestExecutionCondition

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/ExtensionDisabledTests.java


ExtensionDisabledTests.java

Contains “Affiliate” (passes TestExecutionCondition)Contains “Student” (passes studentDetector method )

Contains “Affiliate” (passes TestExecutionCondition)No “Student” (fails studentDetector method )

implements TestExecutionConditionExtension Test

No “Affiliate” (fails TestExecutionCondition)

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/ExtensionDisabledTests.java


Extension PointParameterResolver


Built-in ParameterResolvers

● TestInfo– If a method parameter of type TestInfo is

resolved, JUnit will supply an instance that allows a test to retrieve the display name, tags, test class and test method.

● TestReporter– If a method parameter of type

TestReporter is resolved, JUnit will supply an instance that allows a test to publish entries to the output report.


Extension Test

looks for @UseridTest annotation to return true/false

returns value for given parameters(in the example, a String and a boolean)

UseridParameterResolver.java

implements ParameterResolver

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/extensions/UseridParameterResolver.java


Extension Test

UseridCaseTests.java

implements ParameterResolver

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/UseridCaseTests.java


Extension PointCallbacks


Extension Tests


Extension Test

ChildTests – extends ParentTests

ParentTests – registers extension with class implementing callbacks

class implementing callbacks

Callback Example

implements Callback

Each class prints out the methods available within that class

https://github.com/PennState/junit5-presentation/tree/master/src/test/java/edu/psu/swe/testing/junit5/presentation/callbacks


Extension Testsimplements Callback


Grouped Tests


Grouped Tests

● Traditional For Loop● assertAll()● Factory Tests (@TestFactory)


Collection Testing

Halts test execution when course prerequisite is found

LoopingTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/LoopingTests.java


AssertAll

Executes all test cases inside the assertAll block

LoopingTests.java



Factory Test

Executes all tests regardless of failures

LoopingTests.java



Nested Tests


Nested Tests

FakeSuiteTests.java

https://github.com/PennState/junit5-presentation/blob/master/src/test/java/edu/psu/swe/testing/junit5/presentation/tests/suite/FakeSuiteTests.java


Future Directions


Future

● M3 (September 30, 2016)– JUnit 4 interoperability

– Additional discovery selectors

– Documentation

● M4 (October 30, 2016)– Parameterized tests

– Enhanced dynamic tests


Future

● M5 (November 29, 2016)– Scenario tests

– Repeated tests

– Test execution in user-defined thread


Questions / Comments?


References


References● This presentation

– See the presentation at: http://bit.ly/psu-junit5-j1

– See the code samples at: http://bit.ly/psu-junit5-j1-code

● JUnit 5– Users guide Current Milestone, SNAPSHOT

– Javadocs Current Milestone, SNAPSHOT

– Code and issues Github

http://bit.ly/psu-junit5-j1

http://bit.ly/psu-junit5-j1-code

http://junit.org/junit5/docs/current/user-guide

http://junit.org/junit5/docs/snapshot/user-guide/

http://junit.org/junit5/docs/current/api/

http://junit.org/junit5/docs/snapshot/api/

https://github.com/junit-team/junit5


References

● Articles– Voxxed “JUnit 5 – Setup”

– Voxxed “JUnit 5 – The Basics”

– Voxxed “JUnit 5 – Architecture”

– Voxxed “J Unit 5 – Extension Model”

● Presentations– vJUG “JUnit 5: Next Generation Testing on the JVM”

https://www.voxxed.com/blog/2016/03/junit-5-setup/

https://www.voxxed.com/blog/2016/03/junit-5-basics/

https://www.voxxed.com/blog/2016/04/junit-5-architecture/

https://www.voxxed.com/blog/2016/05/j-unit-5-extension-model/

https://virtualjug.com/junit-5-next-generation-testing-on-the-jvm/

Documents

JUnit 5 - RainFocus · Junit 5: Features, Architecture, and Extensibility - JUnit 5 Steve Moyer Steve Seltzer Niraja Ramesh The Pennsylvania State University