"Test software" (using 9001-1994 terminology) and "computer software" 9001-2000 section 7.6 terminology) to me means this:
I need to test a certain parameter(s) of a product.
I make a measurement(s) of some type and input the measurement(s) into a computer program to do some complex and/or repetitive math calculations for me and spit out the answer.
Also, some of my testing is automated. I hook a computer up to a piece of test equipment, load a sample, run the program, and let the computer control the test instrument, query the instrument for data, calculate (as required) and print-out a test report.
In both cases I need to verify that the computer program does the job correctly before I approve it for use.
I also take some steps (as appropriate) to make sure no one screws with my test software so that it starts doing the wrong things. A password, restricted access, and/or verification of proper functioning before each test are possible appropriate methods to do this.
I hope this helps! If not, write back.