JUnit

"Junit" redirects here. For the Egyptian goddess, see Iunit.

JUnit

Developer(s)	Kent Beck, Erich Gamma, David Saff, Kris Vasudevan
Stable release	5.6.3 / October 26, 2020 (2020-10-26)
Repository	github.com/junit-team/junit5
Written in	Java
Operating system	Cross-platform
Type	Unit testing tool
License	Eclipse Public License (relicensed from CPL before)
Website	junit.org

JUnit is a unit testing framework for the Java programming language. JUnit has been important in the development of test-driven development, and is one of a family of unit testing frameworks which is collectively known as xUnit that originated with SUnit.

JUnit is linked as a JAR at compile-time; the framework resides under package junit.framework for JUnit 3.8 and earlier, and under package org.junit for JUnit 4 and later.

A research survey performed in 2013 across 10,000 Java projects hosted on GitHub found that JUnit (in a tie with slf4j-api), was the most commonly included external library. Each library was used by 30.7% of projects.

Example of JUnit test fixture

A JUnit test fixture is a Java object. With older versions of JUnit, fixtures had to inherit from junit.framework.TestCase, but the new tests using JUnit 4 should not do this. Test methods must be annotated by the @Test annotation. If the situation requires it, it is also possible to define a method to execute before (or after) each (or all) of the test methods with the @Before (or @After) and @BeforeClass (or @AfterClass) annotations.

import org.junit.*;

public class FoobarTest {
    @BeforeClass
    public static void setUpClass() throws Exception {
        // Code executed before the first test method
    }

    @Before
    public void setUp() throws Exception {
        // Code executed before each test
    }
 
    @Test
    public void testOneThing() {
        // Code that tests one thing
    }

    @Test
    public void testAnotherThing() {
        // Code that tests another thing
    }

    @Test
    public void testSomethingElse() {
        // Code that tests something else
    }

    @After
    public void tearDown() throws Exception {
        // Code executed after each test 
    }
 
    @AfterClass
    public static void tearDownClass() throws Exception {
        // Code executed after the last test method 
    }
}

See also

• TestNG, another test framework for Java
• Mock object, a technique used during unit testing
• Mockito mocking extension to JUnit
• EvoSuite, a tool to automatically generate JUnit tests
• List of Java Frameworks

External links

• Official website
• JUnit Presentation
• JUnit Tutorials