Unit testing has been around for quite some time now. It works on the principle of validating an assumption in code. So, even if the code changes after some time, the assumption should remain valid. As it used to test a particular unit of code with a particular assumption, it is referred to as a unit test case. Let's suppose that you are writing a Java class and there are 10 methods in that class, each of them serving 10 different purposes. Then, we can say that you have 10 units of code to be tested. To go with the example, one of the methods is taking ID as input and returning back a Boolean about that ID: is it enabled or disabled in the system. Following is the sample code for a method which checks whether the given ID or, say, user ID is enabled or disabled. :
public boolean isEnable(String Id){
return someRepo.findOne(Id).getStatus().equals("ACTIVE");
} The expected output from this method is either true or false. What happens if the ID does not exist in the database...