Ok. I am confused by this. There is a distinct difference between System Test cases and Unit Test cases. If you are working from a design document detailing the requirements from a working Business or Systems Requirements document and testing the items to make sure that requirements are met you are performing a System Test - a test at a much higher level than Unit Testing. At the Unit Test level you are checking the boundries in the code itself to make sure that loops are exited correctly and logic is performed correctly. In essence a Unit Test is at a component level, intended to look inside the component and make sure that it operates correctly based on it's very limited sets of inputs and outputs. At a higher level, System Test cases look at how the component interacts with other components and wether this interaction meets the requirements. Stupid example using web code: Putting ^5$*1@ in a text search input box is a Unit test case makeing sure that the entry parameters if this code will not barf on the input. System test cases should not need to test this (with a proper procedure for unit testing) but should instead be focusing on if search results are in line with what was requested. These necessary definitions limit and focus the level of your testing and the understanding of the question that is being asked.