If you run the gpg test suite under version 1, you get:
./t-support.h:160: GPGME: Invalid crypto engine FAIL: t-gpgconf
This does not happen if you use gpg2.
Presumably (since e.g. dirmngr tests are skipped under gpg1) the tests should work for both. Is there is a missing feature test for a crypto engine which is absent from gpg1? Perhaps this test should be skipped for gpg1?