2.4.8 Disadvantages of Black Box Testing

• Only a small number of possible inputs can actually be tested, to test every possible input stream would take nearly forever
• Without clear and concise specifications, test cases are hard to design
• There may be unnecessary repetition of test inputs if the tester is not informed of test cases the programmer has already tried
• May leave many program paths untested
• Cannot be directed toward specific segments of code which may be very complex (and therefore more error prone)
• Most testing related research has been directed toward glass box testing