Testing Data : Should I Create a bogus test case?

Question

I've written an Integration program that produces files from a source set of data and converts it to a target data file. These files contain field/record information that must be validated by our clients using their validation methods.

I plan to create numerous test cases and expect to receive information on how well the data validated so I can tweak my program.

I want to create a test case that I know will not pass their validation, however I need to know if their validation methods are picking up basics such as the file structure and layout.

I am trying to prevent the situation if all my test cases pass, but later on the files were not in the correct format the client needed.

Do you feel this is a good idea and would I get any valid information from it?

Answer 1

Yes

that's not a bogus test case, it's a valid test for expected exceptions

• Jon Raynor: Negative test cases are just as good as positive ones. Does it break the way we expect....
• Andy Hunt: Or perhaps more accurately "does it work they way we intended instead of breaking?"?