JUnit

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JUnit

Introduction

JUnit refers to an open source framework that was developed for use in writing and carrying out tests within the Java programming language. Erich Gamma and Kent Beck are credited with the development of the framework, which has become an important element in the growth of the test-driven development process (Beck 43). The test-driven development process itself belongs to a larger design school called Extreme Programming. Additionally, JUnit belongs to a larger family of testing frameworks called xUnit. One of the reasons why JUnit is very popular is that it has a graphical user interface, which makes the process of writing and testing source codes significantly easier (Beck 4). Using JUnit, developers can continually create test suites that measure their progress and find any unexpected side effects. JUnit’s ease of use also comes from the fact that tests can be run continuously, with the developer receiving results instantaneously. Experts describe the process employed by JUnit as “first testing then coding”. Through this process, the developer sets up test data for coding that the framework can test first and then implement (JUnit Tutorial 8). With this approach, the programmer is more productive as they come up with coding that is stable. JUnit is a revolutionary testing framework that has changed the way that developers come up with code, making the process easier and less likely to develop problems.

Background and Features of JUnit

Erich Gamma and Kent Beck first wrote JUnit in 1998 while on a flight from Zurich to Washington D.C. The two developers drew inspiration for the framework from Smalltalk’s SUnit, which Beck also wrote (Beck 43). After its designing, JUnit grew quickly and became one of the most widely used frameworks in the world of Java programming. This popularity also saw the framework inspire other tools within the xUnit family such as nUnit, cppUnit and pyUnit, which carry out tests within other programming languages such as C++, Python and .NET (JUnit Tutorial 9). With these developments, JUnit cemented its place as an important step in the growth of test-driven development.

Certain key features have helped make the JUnit framework quite popular within Java programmers. Users credit these features with making the framework efficient and easy to work with. One of the framework’s key features is its graphical user interface (GUI). The GUI makes JUnit quite simple. This lack of complexity makes it faster and easier for developers to test with it (JUnit Tutorial 8). Developers have also lauded JUnit for the way that the tests run themselves then check the results with the user receiving feedback. This eliminates the need for the programmer to go through the results manually. Additionally, the framework provides users with annotations so they can recognize the test methods as well as assertions that show probable results (JUnit Tutorial 8). Through all of these features, the JUnit framework is easy for programmers to work with as it ultimately makes developer capable of writing their code faster and more efficiently.

Benefits and Constraints of JUnit

A range of advantages that the framework offers over other methods has enhanced JUnit’s popularity within the world of Java programming. These advantages make it easier for developers to use the framework and come up with better coding. Firstly, JUnit provides users with an alternative to writing and running tests for every code that they write. With JUnit, developers are able to come up with a way of testing their code progressively as the write it, in an automated process that saves time and makes the work more efficient (JUnit Tutorial 8). The automated testing also makes it possible for developers to test the entire function in the event of small or large changes to a code. This ability to test the entire function easily means that the user can make sure that any changes that they make do not affect other sections of their work (JUnit Tutorial 8).

Another advantage of using JUnit comes from the fact that it has become very popular among developers meaning that the framework is supported by most Integrated Development Environments (IDEs) such as Eclipse and Netbeans. This means that anybody working in the average IDE will find support for the JUnit framework within the environment. Additionally, a combination of JUnit and some IDEs provides the developer with a wizard that can assist them in the execution of test cases (JUnit Tutorial 8). The ease of using JUnit also provides programmers with another advantage by making it possible for a new member to join the development team when the process has already started. The simplicity of JUnit makes it possible for the new member to view and understand the test cases that the rest of the team had already developed. This can allow them to contribute to the team, despite not being present in the earlier parts of the design process. Experts also state that one of JUnit’s largest benefits is the fact that it makes it possible for users to create and handle extensive test case suites (JUnit Tutorial 8).

JUnit developer Kent Beck explains that JUnit provides its users with an advantage by making it possible for them to run multiple tests of their coding at once and then summarize the results in a simplistic way (9). Additionally, users can then compare the test results with the ones that they expected from their own projections and anticipations. This advantage is compounded by the fact that the JUnit framework gives the programmers a convenient location for gathering the tests that they have written. Lastly, JUnit gives developers a good location for sharing the code that they applied when creating the items that they plan to test (Beck 9).

As with all other testing methods and framework, JUnit has some disadvantages. Beck acknowledges that there are certain constraints that emerged within the framework as the developers tried to make it as simple and automated as possible (9). Firstly, the framework’s advantage of making the tests easy to write and read is countered by the fact that users have to learn yet another group of tools related to programming (Beck 9). Secondly, sometimes the user needs to run tests within an isolated environment that ensures that their impact does not affect previous or unrelated results. Beck acknowledges that the process of isolating a test can be long and tedious (9). The creators of the JUnit framework reduced the impact of these limitations by making it possible for JUnit to use basic Java as the testing language and by taking advantage of the platform’s orientation towards isolation (Beck 10).

Using JUnit

The installation of JUnit in the users requires certain requirements to be present. Since JUnit is a framework for testing code in the Java programming language, the primary requirement for the software is the Java Development Kit (JDK). JUnit requires the user to have JDK 1.5 and above installed in their system (JUnit Tutorial 10). If the user does not have the Java Development Kit installed, they can obtain the software from http://www.oracle.com/technetwork/java/javase/downloads/index.html. With Java installed, the next step is supposed to be the installation of the JUnit framework in the user’s computer. The user starts by downloading the most recent version of the framework from www.junit.org/. The next step sees the user uncompress the zip file into the location they prefer. Lastly, the user adds the path to the location where their JUnit framework was extracted into their Java classpath environment variable (JUnit Tutorial 10).

The first step in using the JUnit framework requires the user to create a class that the software can then test. The classes in JUnit are an important aspect of the framework as they are used to write and test. Examples include assert, Testcase and Testresul (JUnit Tutorial 25). Normally, programmers use the basic classes along with test case classes and test runner classes. A good example of these elements is the assert class, which contains all of the assertions. When combined with annotations, assertions help to make the work easier for the user.

Assertions

Within the JUnit framework, assertions are normally found in the assert class. These assertion methods normally make it easier for the user to write the tests that they are using. Normally, the framework only records the assertions that failed after the user stipulated them (JUnit Tutorial 28). The JUnit framework has some important methods within the assert class. Void assertEquals(Boolean expected, Boolean actual) confirms whether two primitives or objects are equal. Void asserttrue(Boolean expected, Boolean actual) looks to see whether a condition is true. Void assertfalse(Boolean condition) confirms that a condition is false. Users can apply other assertion methods to see whether objects are null or not and if one array is equal to another (JUnit Tutorial 28).

Annotations

Annotations are another important feature of the JUnit framework for Java programming. Developers use annotations by adding them to their coding and then applying them to different methods and within classes. Within JUnit, annotations provide the programmer with information about test methods by letting them know the methods that JUnit will execute after and before the test methods, the order in which all other methods will be carried out and the ones that will be completely ignored (JUnit Tutorial 30). Examples of annotations include @test (it instructs JUnit to execute the method it is attached to as a test case); @before (methods annotated with this are carried out before the text method); @after (ensures that JUnit operates the attached method after the test method) (JUnit Tutorial 30).

Conclusion

Since its development in 1998 by Erich Gamma and Kent Beck, the JUnit framework for testing Java coding has proven to be an immense success, revolutionizing the way developers carry out their work. The fact that experts have developed similar frameworks for programming languages such as Delphi, .NET and C++ is evidence of the popularity that JUnit has within the programming community. In essence, JUnit provides an automated system for programmers to run tests of their coding, with the tests capable of periodically checking whether any changes made have affected other parts of the code. This system, combined with a basic GUI and simple design, has made JUnit the preferred testing framework for programmers as it helps make them more efficient at their work, while making the main task easier.

Works Cited:

Beck, Kent. JUnit Pocket Guide. Sebastopol, Calif: O’Reilly Media, 2004. Print.

“JUnit Tutorial.” Tutorialspoint. Tutorialspoint, 2014. Web. 04 March 2014.