[erlang-questions] common test perform coverage analysis on large lib

Peter Andersson <>
Fri Mar 19 10:55:16 CET 2010

Hi Chengwei,

Unfortunately there's no support for running cover from the ct_master as
of yet. ct_master passes the testspec on to the ct nodes, so cover will
run on each node as expected. But then what exactly goes wrong during
cover analysis I can't say without first doing a bit of investigation.
In any case, proper support for cover in a "large scale testing"
environment should provide the option to use the master node as central
node also for the cover data collection and analysis (so the result can
include all execution on all nodes). This feature could be introduced
simply by allowing a {cover, master, MasterCoverFile} term in the test
specification. I.e. the existing {cover, CoverFile} would mean "run
cover analysis locally on each node" (which "almost" works already...),
while the new term would state "collect and analyse coverage of all
tests, and print the cover logs, on the master node". Cool! I'll add
this to the list of proposed new features for CT. Thanks!


Erlang/OTP, Ericsson AB

Aeolus wrote:

> hi,
> we used common test to perform coverage analysis on our system, the
> problem is it hangs when giving the "Coverage analysing...“ msg, we
> suspect this could be due to common test and our system is competing
> for file writing access. so our question is it possible to run
> coverage with ct_master module so it will run test on slave node but
> do coverage updating at master node. we tried to feed master node with
> test spec and it seems it skipped execution of {cover, "cover.file"}
> opt. We use R12 of erlang.
> thx in advance.
> //Chengwei
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