[tor-dev] lcov test coverage reports

Nick Mathewson nickm at freehaven.net
Fri Jun 20 16:16:34 UTC 2014

On Mon, Jun 16, 2014 at 4:07 PM, Nick Mathewson <nickm at freehaven.net> wrote:
> On Mon, Jun 16, 2014 at 10:55 AM, Nick Mathewson <nickm at freehaven.net> wrote:
>  [...]
>> Additionally, one thing that I'd really love to see -- though I don't
>> at all know whether lcov can do this as it stands -- is a semantic
>> diff between two coverage outputs.  When writing new unit tests at
>> random, or when checking functions that you know need coverage, it's
>> useful to ask "Which lines are not covered?"  But for validating new
>> code and checking patches, the question I want to ask is "Which *new*
>> or *changed* lines are not covered?"
>> We kinda have a script for this now, but learning to read its outputs
>> is not as easy as I'd like.
> It would appear at first glance that you can do something *almost*
> like this using lcov --diff and genhtml --highlight.  Those options
> together seem to be able to let you know about lines that used to be
> covered but which are no longer covered.  (I'm hoping to learn about
> likes that changed or started to exist which are uncovered.)

I asked this question on the ltp list, and got an answer:


This is a kludge too, but we should investigate whether it's better
than our current kludge.


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