What is JUnit?
JUnit is a widely used testing framework for the Java programming language. It is an open-source framework designed to write and run repeatable tests. It provides annotations and assertions for writing tests, and it also has a test runner which can run the tests and report the results.
JUnit can be used to test different types of Java code, such as unit tests for individual classes and methods, integration tests for testing how different parts of an application work together, and acceptance tests for testing the application as a whole.
JUnit provides several annotations that can be used to define test methods, test classes, and test suites. For example, the @Test annotation is used to mark a method as a test method, the @Before and @After annotations are used to run some code before and after each test method, and the @Ignore annotation can be used to skip a test method.
JUnit also provides assertions, which are used to check that the actual results of a test match the expected results. For example, the assertEquals method can be used to check that two values are equal, and the assertTrue method can be used to check that a Boolean expression is true.
JUnit is widely used in the Java world, it’s integrated into many development environments, and it’s also integrated with other tools such as build tools (e.g. Maven, Gradle) and continuous integration servers (e.g. Jenkins), making it easy to run tests automatically as part of the development process. JUnit is also commonly used in conjunction with other testing frameworks such as Mockito to perform unit testing, integration testing, and acceptance testing.