WHAT IS A TEST CASE? IEEE Standard 610 (1990) defines test case as follows: A set of test inputs, execution conditions, and expected results developed for a particular objective, such as to exercise a particular program path or to verify compliance with a specific requirement.
The following may be the example for the priority scale 1-4
P1 - These are the test cases that are run first to determine if a given build is even testable.
P2 - These are the test cases that are executed the most often to ensure functionality is stable, intended behaviors and capabilities are working.
P3 - These are the test cases where the testing of a given functional area or feature is to get more detailed and the majority of aspects for the function are examined including boundary, error and configuration tests.
P4 - These are the test cases that are frequently tested. They are may or may not be tested. It does’nt mean those are not important but just that they are not run often in the life of the project.
FMEA is a technique for systematically identifying potential failures in a system or process. It can also be used for understanding and prioritizing possible failure modes. But use FMEA only if it is appropriate.