3 korrents from this piece
Every claim below was made in this piece, quoted word for word and numbered in the order the piece makes them, so you can read it there rather than take our word for it. The sentence above each quote is our reading of the claim, not their wording. Each quote was checked against a stored copy of the page at build time; where the two differ, the quote is the fact.
Our reading
Test coverage is a tool for finding untested code and says nothing about how good the tests are.
Their wordsTest coverage is of little use as a numeric statement of how good your tests are.
Their wordsIf you make a certain level of coverage a target, people will try to attain it. The trouble is that high coverage numbers are too easy to reach with low quality testing.
Their wordsI would be suspicious of anything like 100% - it would smell of someone writing tests to make the coverage numbers happy, but not thinking about what they are doing.