Embracing with Eclipse JUnit 5 with...5 JUnit Platform junit-platform-launcher Launcher APIs used by IDEs and build tools to launch the framework. Finds test engines via Java’s ServiceLoader

Noopur Gupta

Eclipse JDT co-lead

IBM India

[email protected]

Embracing

with

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@noopur2507

EclipseCon Europe 2017 | Embracing JUnit 5 with Eclipse | Noopur Gupta, IBM

JUnit 4.0 Released in 2006

JUnit 5.0 Released in September 2017

2Source: http://blog.takipi.com/the-top-100-java-libraries-in-2017-based-on-259885-source-files/

JUnit Framework


The top 20 Java libraries on GitHub in 2017

http://blog.takipi.com/the-top-100-java-libraries-in-2017-based-on-259885-source-files/

Modularity (single JAR)

Developers accessing internals and duplicating code

Maintainability

Extensibility(via Runners and Rules)

Java 8 support(Lambdas, Streams, Default Methods etc.)

JUnit 4 Architecture

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junit.jar(Single JUnit 4 JAR)

Testing frameworks developers

Build tools developers

IDEs developers

@Test developers

Problems

(+ org.hamcrest.core.jar)


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JUnit 5 = Platform + Jupiter + Vintage

5th planet in Solar System!

Source: http://junit.org/junit5/docs/current/user-guide/#dependency-diagram


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

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JUnit Platform ▪ junit-platform-launcher

Launcher APIs used by IDEs and build tools to launch the framework.Finds test engines via Java’s ServiceLoader mechanism.

▪ junit-platform-engine

TestEngine APIs for integration of any testing framework that runs on platform.

JUnit Jupiter ▪ junit-jupiter-api

APIs for the new programming and extension model.▪ junit-jupiter-engine

JupiterTestEngine - To discover and execute Jupiter tests.

JUnit Vintage▪ junit-vintage-engine

To discover and execute JUnit 3 and JUnit 4 tests on JUnit 5 platform.



A sneak peek into the major interesting features of JUnit Jupiter with Eclipse support for JUnit 5.

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Eclipse support for JUnit 5

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Eclipse Oxygen.1a (4.7.1a)https://www.eclipse.org/downloads/eclipse-packages

Eclipse Photon (4.8) M2 onwardshttp://download.eclipse.org/eclipse/downloads

Software site repository to update Eclipse Oxygen (4.7 and 4.7.1):http://download.eclipse.org/releases/oxygen/

Demo: Eclipse Photon (4.8) M2 milestone build


https://www.eclipse.org/downloads/eclipse-packages

http://download.eclipse.org/eclipse/downloads

http://download.eclipse.org/releases/oxygen/

Demo

JUnit Jupiter - Programming Model

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Create a new JUnit Jupiter test

Create a new JUnit Jupiter test inEclipse with lifecycle method stubsfor a class and its methods under test:

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New JUnit Test Case wizard-> New JUnit Jupiter test


Add JUnit 5 library to the build path

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New JUnit Test Case wizard offers to add it while creating a new JUnit Jupiter test.

Quick Fix (Ctrl+1) proposal on @Test.

Add library (JUnit) in Java Build Path dialog.


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Visibility

Test classes and methods can have any accessmodifier (other than private).

Annotations

JUnit 4 JUnit Jupiter

@org.junit.Test @org.junit.jupiter.api.Test(No expected and timeout attributes)

@BeforeClass @BeforeAll

@AfterClass @AfterAll

@Before @BeforeEach

@After @AfterEach

@Ignore @Disabled


Create a JUnit Jupiter test method in Eclipse with the new template:

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test_jupiter


Create a new JUnit Jupiter test method

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Assertions(org.junit.jupiter.api.Assertions class)

• Failure message comes at the end of arguments list.

• Failure message can be retrieved lazily.

• Grouped assertions to execute all assertions first and then report all failures together.

• Exception testing to assert and evaluate a thrown exception.

• Asserting that the given task completes before the given timeout.


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(org.junit.jupiter.api.Assumptions class)


Assumptions

JUnit Jupiter’s Assertions, Assumptions, DynamicContainer & DynamicTest classes are now added to Eclipse Favorites by default.

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Preferences

-> Java -> Editor

-> Content Assist

-> Favorites

Import static methods in your code from favorite classes via Content Assist (Ctrl + Space) and Quick Fix (Ctrl + 1).

Configure the number of static member imports needed before type.* is used.


Eclipse Favorites

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@DisplayName

Provide custom display names for test classes and test methods - with spaces, special characters, and even emojis!

Use Go to File action or just double-click to navigate to the test from JUnit view.


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@Nested test classes Non-static nested classes (i.e. inner classes) can serve as @Nested tests for logical grouping of test cases.

(Re-)Run a single @Nested test class by using the Run action in JUnit view or Outline view.You can even right-click on a nested test class name in the editor and use the Run As action.

Example: TestingAStackDemo in JUnit 5 user guide.


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Test interfaces and default methods

• Default test methods can be inherited by implementing test classes.

• Enables multiple inheritance in tests classes.

Example: StringTests in JUnit 5 user guide.


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Tagging and Filtering

• Tag test classes and test methods with @Tag.

• Tags can later be used to filter test execution.


Provide tags to be included inor excluded from a test runvia Configure Tags dialog in itsJUnit launch configuration.

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Meta-annotations and composed annotations

• JUnit Jupiter annotations can be used as meta-annotations.

• Create custom composed annotation inheriting semantics of its meta-annotations.


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Dynamic Tests• Dynamic tests are generated at runtime by a @TestFactory method.

Create a @TestFactory method in Eclipse with the new template:

• Dynamic container is composed of a display name and a list of dynamic nodes.

• Dynamic test is composed of a display name and an Executable.

test_factory


There are no lifecycle callbacks for individual dynamic tests.

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Navigate to failing source location

Double-click an entry in JUnit view’s failure trace to jump to the corresponding source location.

Click "Show Stack Trace in Console View" button and use the hyperlinks.It can also be used to copy parts of the stack trace.


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Dependency Injection• Test constructors and methods are now permitted to have parameters enabling

Dependency Injection.

• ParameterResolver is the extension API to provide a parameter resolver whichdynamically resolves a parameter at runtime.

• A parameter resolver can be registered via @ExtendWith(…) annotation.

• JUnit Jupiter provides some built-in resolvers which are registered automatically:

o TestInfo (resolved by TestInfoParameterResolver) to access information about the currently executing test:


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Dependency Injection

o TestReporter (resolved by TestReporterParameterResolver) to publish additional data from the currently executing test which can be seen in the Console view in Eclipse:

• To support overloaded test methods, the Test Method Selection dialog in JUnit launch configuration now shows the method parameter types also:


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Repeated Tests

Repeat a test by annotating the method with @RepeatedTest and specifying thenumber of repetitions.

• name attribute: to optionally specify a custom display name for each repetition.

• RepetitionInfo: as test method parameter to get information about the currentrepetition.


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Parameterized Tests

Run a test multiple times with different arguments by:

• annotating the method with @ParameterizedTest• and declaring at least one source to provide the arguments.

• name attribute: to optionally specify a custom display name for each invocation.• Test method may have additional parameters to be resolved by other

ParameterResolvers at the end of the method's parameter list.


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Test Instance Lifecycle

• By default, JUnit Jupiter creates a new instance of the test class beforeexecuting each test method.

• To execute all test methods on the same instance of the test class, you canannotate the test class with @TestInstance(Lifecycle.PER_CLASS).

• The per-class mode makes it possible to use @BeforeAll and @AfterAllannotations on:

oNon-static methods

o Interface default methods

oMethods in @Nested test classes


JUnit Jupiter - Extension Model

See the JUnit 5 User Guide for more details.

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Provides extension points as interfaces in org.junit.jupiter.api.extensionpackage to be implemented by extension providers.

Register one or more extensions declaratively on a test class, test method,or composed annotation with @ExtendWith(…).

JUnit Jupiter also supports global extension registration via Java’sServiceLoader mechanism.


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

In summary…

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Modular architecture

Modern programming model

Powerful extension model

Gentle migration path

Eclipse IDE support


References & ResourcesEclipse support for JUnit 5

https://www.eclipse.org/community/eclipse_newsletter/2017/october/article5.php

Download Photon (4.8) M2 & above: http://download.eclipse.org/eclipse/downloads

Download Oxygen.1a (4.7.1a): https://www.eclipse.org/downloads/eclipse-packages

Software site to update Oxygen (4.7 & 4.7.1): http://download.eclipse.org/releases/oxygen/

Report bugs/enhancements: https://bugs.eclipse.org/bugs/enter_bug.cgi?product=JDT

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https://www.eclipse.org/community/eclipse_newsletter/2017/october/article5.php

http://download.eclipse.org/eclipse/downloads

https://www.eclipse.org/downloads/eclipse-packages

http://download.eclipse.org/releases/oxygen/

https://bugs.eclipse.org/bugs/enter_bug.cgi?product=JDT

References & ResourcesJUnit 5 Project

http://junit.org/junit5

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

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

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

Gitter https://gitter.im/junit-team/junit5

Q&A http://stackoverflow.com/questions/tagged/junit5

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http://junit.org/junit5

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

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

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

https://gitter.im/junit-team/junit5

http://stackoverflow.com/questions/tagged/junit5

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Eclipse Converge 2017 | Embracing JUnit 5 with Eclipse | Noopur Gupta, IBM

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Documents

Embracing with Eclipse JUnit 5 with...5 JUnit Platform junit-platform-launcher Launcher APIs used by IDEs and build tools to launch the framework. Finds test engines via Java’s ServiceLoader