JUnit

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 GitHub projects found that JUnit, along with slf4j-api, are the most popular libraries. Each library was used by 30.7% of projects. ^[3]

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.^[4] Test methods must be annotated by the @Test annotation. If the situation requires it,^[5] 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.^[4]

import org.junit.*;
 
public class TestFoobar {
    @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 
    }
}

Ports

JUnit alternatives have been written in other languages including:

• Actionscript (FlexUnit)
• Ada (AUnit)
• C (CUnit)
• C# (NUnit)
• C++ (CPPUnit)
• Coldfusion (MXUnit)
• Erlang (EUnit)
• Eiffel (Auto-Test) - JUnit inspired getest (from Gobosoft), which led to Auto-Test in Eiffel Studio.
• Fortran (fUnit, pFUnit)
• Delphi (DUnit)
• Free Pascal (FPCUnit)
• Haskell (HUnit)
• JavaScript (JSUnit)
• Microsoft .NET (NUnit)
• Objective-C (OCUnit)
• OCaml (OUnit)
• Perl (Test::Class and Test::Unit)
• PHP (PHPUnit)
• Python (PyUnit)
• Qt (QTestLib)
• R (RUnit)
• Ruby (Test::Unit)

See also

• TestNG, another test framework for Java
• Mock object, a technique used during unit testing
• Mockito and PowerMock, mocking extensions to JUnit

References

External links

• Official website
• JUnit antipatterns (developerWorks) and JUnit antipatterns (Exubero)
• An early look at JUnit 4
• JUnit Presentation
• JUnit different APIs with Examples
• JUnit Tutorials