The target audience for unit tests is not the client, it is the developer. Unit tests allow you to change code with more confidence. 100% code coverage is not a useful aim, you should aim for 100% confidence in your code. Unit tests can also function as example code, that can't get out of date, since then the tests will fail.
Testing for quality assurance is a different thing, usually called acceptance testing and sometimes including regression testing. One easy way to make clients angry is by re-introducing bugs that were fixed in earlier releases.
Testing for quality assurance is a different thing, usually called acceptance testing and sometimes including regression testing. One easy way to make clients angry is by re-introducing bugs that were fixed in earlier releases.