When asked about my point of view about a guideline concerning code coverage, my answer always is: go for 100% code coverage. 100%, unless... Here is why. When the guideline for code coverage is 80% (not an uncommon guideline) the devil is in the details...
Test Driven Development is hot, just like unit testing your software and any other kinds of (automated) testing. And as we all know: sometimes stuff that's hot is misinterpreted, explained wrong or just simply used in a really bad way. Unfortunately...