test/signature: more targeted signature tests
test/signature: more targeted signature tests

Testing against invalid signature should be done in cms_verify() instead
of cms_verify_file().

In cms_verify_file() instead it makes sense to test also the impact of
the offset argument on the verification process.

Additionally extend tests to test for returned objects.

Signed-off-by: Enrico Joerns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,ejoerns/rauc,rauc/rauc,jluebbe/rauc,jluebbe/rauc,rauc/rauc,rauc/rauc