This Spring controller unit test is based on

HATEOAS RESTFul Service with Spring tutorial. The request URL and JSON response content are shown below.

REQUEST URL: http://localhost:8080/simpleSpring/greeting?name=John
RESPONSE JSON: {“content”:”Hello, John!”,”links”:[{“rel”:”self”,”href”:”http://localhost:8080/simpleSpring/greeting?name=John”}]}

REQUEST URL: http://localhost:8080/simpleSpring/greeting
RESPONSE JSON:{“content”:”Hello, World!”,”links”:[{“rel”:”self”,”href”:”http://localhost:8080/simpleSpring/greeting?name=World”}]}

The first step is to have the relevant jars for testing in the pom.xml…

This assumes that you have gone through the basic JUnit & Mockito tutorials. Here is test class to “Unit Testing Servlet Filter”. The “HttpServletRequest“, “HttpServletResponse“, “FilterChain“, etc are mocked with Mockito. The Spring also provides classes like “MockHttpServletRequest“, etc.