{"id":1371,"date":"2015-06-30T07:22:45","date_gmt":"2015-06-30T11:22:45","guid":{"rendered":"http:\/\/springframework.guru\/?p=1371"},"modified":"2019-06-16T07:33:09","modified_gmt":"2019-06-16T11:33:09","slug":"unit-testing-junit-part-2","status":"publish","type":"post","link":"https:\/\/springframework.guru\/unit-testing-junit-part-2\/","title":{"rendered":"Unit Testing with JUnit \u2013 Part 2"},"content":{"rendered":"

In the first part<\/a> of the series on unit testing with JUnit, we looked at creating unit tests both using Maven and IntelliJ. In this post, we will look at some core unit testing concepts and apply those using JUnit constructs. We will learn about assertions, JUnit 4 annotations, and test suites.<\/p>\n

JUnit Assertions<\/h2>\n

Assertions, or simply asserts provide programmers a way to validate the intended behavior of code. For example, through an assertion you can check whether a method returns the expected value for a given set of parameters or a method correctly sets up some instance or class variables. When you run the test, the assertion executes. If the method under test behaves exactly as you specified in the assertion, your test passes. Otherwise, an AssertionError<\/code> is thrown.<\/p>\n

JUnit provides support for assertions through a set of assert methods in the org.junit.Assert<\/code> class. Before we start using them, let’s have a quick overview of the Arrange, Act, Assert (AAA) pattern. This pattern is the recommended way to write unit test methods where you divide a method into three sections, each with a specific purpose:<\/p>\n