The Testing Process I1 Testing Programs Even a non-programmer can test a program. In fact each of us evaluates a program when we run it for a first time. Does it do what we expect? –Does the word processor lose documents? –Does the bank account program give bad sums? Does it do what we would like it to do? –Does the word processor check the grammar? Is it graceful and easy to use?

The Testing Process I2 Testing for Correctness Does the program do what is expected. That is the primary task of a program. Are the sums correct? Check the arithmetic. When values are sought that are “outside of the box” does the program correctly handle this unexpected problem? Does the program “crash” for no apparent reason?

The Testing Process I3 Testing for Usability Less critical, but still important is a question of how the program communicates with the user Are the messages meaningful and appropriate? Is the placement of material on the form suitable to the task? Are the colors pleasing and well coordinated? Is the program modest?

The Testing Process I4 Test for Correctness, Example 1 There is only one way to test for the correctness of an algorithm and that is to do the arithmetic and see if it works. Sometimes this is easy.

The Testing Process I5 Test for Correctness, Example 2 Sometimes this is not. In any event, the problem resolves itself into doing the work by hand.

The Testing Process I6 Test for Correctness, Example 3 Working outside of the box. A program should be ready to accept impossible data and handle it correctly.

The Testing Process I7 Test for Usability, Example 1 Even some thing as simple as a misspelled word makes a program less usable.

The Testing Process I8 Test for Usability, Example 2 Good vs. Bad Interaction