To assert static objects, we either have to add a method into the
object under test itself and recompile on a test run with the activated test
method (but also recompile after tests, so that method is gone on
release builds).
Alternatively we can include the whole .c file in our test
infrastructure and save the object in the test directory. So there's no
necessity to clean it up prior to a release build and it's contained
away.
This requires, that the test folder isn't excluded in coveralls.
To replace all occuring format strings inside the msg, replace_all had
been used previously. This leads to buggy behavior, if a format string
occurs in the replaced text, as the format string will get replaced
again under certain conditions.
Introducing a pointer, which skips the already replaced parts, will
prevent doubly replacing format strings from content.
Fixes#322
