What is code coverage?
Code coverage is a way to see how many statements in your database code have been executed when you ran your tests(s). It is a way to see how well covered with tests a particular area is – the better covered with tests, the less likely you will miss issues when you make changes in those areas.
What is code coverage for SQL Server?
SQL Server gives us a great tracing mechanism, either profiler or extended events which details exactly which statements have been run. SQL Server doesn’t do so well at telling us what statements we could possibly run in some code but the Transact Sql Script Dom that is part of the DacFx does give us the ability to break T-SQL code into statements so combining the two we have the ability to take a stored procedure such as:
This is pretty snazzy.