How much testing is sufficient? Or, is it possible to do exhaustive testing of the software?

Question

Consider a simple program that takes a string as an input that is ten characters long.

Answer 1

I have yet to see an enterprise application of any significant complexity that had sufficient test automation. I've seen huge test suites with great code coverage metrics. Most of those had such atrocious run times that they were nearly unusable.

Answer 2

In your case, where a simple program that takes a string as an input that is ten character long, I would run the following test cases to ensure that its testing is done and is working as per the needs;

• Test with 10 characters
• Test with no input
• Test with 1 character
• Test with 11 characters
• Test with 10 numbers
• Test with special characters

That should be enough.