When we try to decode with the wrong decryption key, we could get any number of
error messages, depending on what failure mode we are in (couldn't authenticate
plaintext after decryption, couldn't deserialize, etc.). This change makes the
test weaker, but at least we know we will get an error message in the case where
the decryption key is wrong.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
Note that we don't cache the securecookie.SecureCookie that we use in our
implementation. This was purely because of laziness. We should think about
caching this value in the future.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>