Test Methods 

Definition

Test methods are instance methods without parameters of test classes and are declared using the FOR TESTING addition to the METHODS statement. Each test method corresponds to an ABAP Unit test. In a test method, you implement the test code by calling production sections of the program and checking the results with the methods of the system class CL_AUNIT_ASSERT.

Test methods should be private. If they are public or protected the methods are inherited. Since test classes implicitly offer friendship to the test driver in the runtime environment, the driver can call them.