There are many places to visit it the world and it can be interesting to see “where you’ve been”. There are many places in the software for tests to visit, and seeing “where the tests have been” can be very interesting for testers.
Dot Graham explains what coverage is, and why it can be misleading to talk about 100% coverage. Coverage is a relationship between the tests and the software being tested, and is an objective measurement of some aspect of thoroughness of the testing.
There ways in which the term coverage is mis-used, and four caveats of coverage which you should be aware of.
So, is coverage a good thing to have? In other words, should testing be thorough? Not necessarily; sometimes testing should be more like strawberry jam than butter or margarine.
Whenever you hear the term “coverage”, there two important questions that you should always ask: Coverage of what? and Why?