Handle wide-strings similarly to how normal strings are already handled.
For now support for them is only available in the ODBC backend.
Also add conversion functions between UTF-{8,16,32} and wchar_t and the
tests for them. Note that some of these functions are not used yet, but
provide the complete set as they probably will be in the future.
Co-Authored-By: Vadim Zeitlin <vz-soci@zeitlins.org>
This allows to compile them once, instead of doing it for every backend:
while this doesn't matter for the CI builds, recompiling common-tests.h
a dozen times enormously slowed down local builds using all backends.
Now it is compiled only once, as test-common.cpp, and all the other
tests (except for the "empty" one) just link with the resulting library.
Also extract some parts of this file into separate headers, that can be
included only by the tests that actually need them.
Note that the entire test-common.cpp probably ought to be split into
multiple files, to speed up its build too, but this can be done later.
This should solve compilation errors on OSX where struct session defined in
global namespace in /usr/include/sys/proc.h conflicts with unqualified uses of
soci::session.
Fixes#340
"assert" in the name of the directory doesn't make any sense any more as we
don't use asserts in the test code now that we use CATCH.
Also extend the tests description in the README.md.
Robert Adam