{"id":31893,"date":"2014-11-10T16:00:28","date_gmt":"2014-11-10T14:00:28","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/?p=31893"},"modified":"2023-12-05T16:01:59","modified_gmt":"2023-12-05T14:01:59","slug":"junit-tutorial-unit-testing","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2014\/11\/junit-tutorial-unit-testing.html","title":{"rendered":"JUnit Tutorial for Unit Testing \u2013 The ULTIMATE Guide (PDF Download)"},"content":{"rendered":"

EDITORIAL NOTE:<\/strong> We have provided plenty of JUnit<\/a> tutorials here at Java Code Geeks, like JUnit Getting Started Example<\/a>, JUnit Using Assertions and Annotations Example<\/a>, JUnit Annotations Example<\/a> and so on.<\/em><\/p>\n

However, we prefered to gather all the JUnit<\/a> features in one detailed guide for the convenience of the reader. We hope you like it!<\/p>\n

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Table Of Contents<\/h3>\n
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1. Unit testing introduction<\/a><\/dt>\n
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1.1. What is unit testing?<\/a><\/dt>\n
1.2. Test coverage<\/a><\/dt>\n
1.3.Unit testing in Java<\/a><\/dt>\n<\/dl>\n<\/dd>\n
2. JUnit introduction<\/a><\/dt>\n
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2.1. JUnit Simple Example using Eclipse<\/a><\/dt>\n
2.2. JUnit annotations<\/a><\/dt>\n
2.3. JUnit assertions<\/a><\/dt>\n<\/dl>\n<\/dd>\n
3. JUnit complete example using Eclipse<\/a><\/dt>\n
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3.1. Initial steps<\/a><\/dt>\n
3.2. Create a java class to be tested<\/a><\/dt>\n
3.3. Create and run a JUnit test case<\/a><\/dt>\n
3.4. Using @Ignore annotation<\/a><\/dt>\n
3.5. Creating suite tests<\/a><\/dt>\n
3.6. Creating parameterized tests<\/a><\/dt>\n
3.7. Rules<\/a><\/dt>\n
3.8. Categories<\/a><\/dt>\n<\/dl>\n<\/dd>\n
4. Run JUnit tests from command line<\/a><\/dt>\n
5. Conclusions<\/a><\/dt>\n<\/dl>\n<\/div>\n

 <\/p>\n

<\/a>1. Unit testing introduction<\/h2>\n

<\/a>1.1. What is unit testing?<\/h3>\n

A unit can be a function, a class, a package, or a subsystem. So, the term unit testing refers to the practice of testing such small units of your code, so as to ensure that they work as expected. For example, we can test whether an output is what we expected to see given some inputs or if a condition is true or false.<\/p>\n

This practice helps developers to discover failures in their logic behind their code and improve the quality of their code. Also, unit testing can be used so as to ensure that the code will work as expected in case of future changes.<\/p>\n

<\/a>1.2. Test coverage<\/h3>\n

In general, the development community has different opinion regarding the percentage of code that should be tested (test coverage). Some developers believe that the code should have 100% test coverage, while others are comprised with a test coverage of 50% or less. In any case, you should write tests for complex or critical parts of your code.<\/p>\n

<\/a>1.3. Unit testing in Java<\/h3>\n

The most popular testing framework in Java is JUnit<\/a>. As this guide is focused to JUnit, more details for this testing framework will presented in the next sections. Another popular testing framework in Java is TestNG<\/a>.<\/p>\n

<\/a>2. JUnit introduction<\/h2>\n

JUnit<\/a> is an open source testing framework which is used to write and run repeatable automated tests, so that we can be ensured that our code works as expected. JUnit<\/a> is widely used in industry and can be used as stand alone Java program (from the command line) or within an IDE such as Eclipse.<\/p>\n

JUnit provides:<\/p>\n