Specification Enforcement

"The French don't care what you do, so long as you pronounce it correctly."

"My Fair Lady", Rogers and Hammerstien

Specifications provide a means to record the intentions of the developers. Test engineers use specifications to verify that the actual product matches the developers' intentions.

The degree to which verification is possible depends on the level of detail in the specification. The degree to which verification is necessary depends on the product quality goals.

• Verification
• Ensure that the product and specification match.
• Did we build the thing right?
• Tests assume the specification is correct, but not necessarily complete.
• Validiation
• Ensure that the product meets requirements.
• Did we build the right thing?
• Formal validation is most often applied in areas where there is only one correct answer (medical instruments), or the cost of failure is very high (aviation).

All software products have some level of specification.

• user documentation
• functional specifications
• detail design documents

The maximum level of detail in the documentation tends to directly correlate to the maximal depth of testing. Testing based on the low level implementation (i.e. reading the code) is usually done in unit tests, which may or may not be the reponsibility of test engineers.

Copyright 1998 Anne Powell