* Change VerifyType to return an error instead of panicking
Signed-off-by: Vincent Demeester <vdemeest@redhat.com>
* Move the use of `VerifyType` in tests
Those calls to `duck.VerifyType` are done at runtime and thus could be
costly at program startup. Putting them under tests ensure we still
assert those types but during unit testing.
Signed-off-by: Vincent Demeester <vdemeest@redhat.com>