This is usually true. You have to have some way to drive the units in a controlled manner. There are some instances where you could use the application to perform the unit testing but it makes controlling it more difficult and in some cases nearly impossible and more work than you really want in a unit test. That is if the application is integrated enough for you to even use it. Typically it isn't at the unit testing point in new development. Then there are test harnesses. If you already have one built for your use you may not have to do any new coding.
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not "Eureka!", but "That's funny..."
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not Eureka!, but That's funny...
There are products that do exist in the marketplace that will allow you to unit test without coding a framework. However, all unit testing tools, even if they advertise that they don't require custom coding, do require coding to setup environment variables, database entries, etc. These unit testing tools are very dependant on your devlopment platform. For example, if you are unit testing java, I know of only two tools: IQTest by Class I.Q. and JTest by parasoft. Both have pluses and minuses, but to each his own...