Fix more issues with gating tests

tests/tests.yml

@@ -13,7 +13,9 @@
     required_packages:
     - python3-cryptography
     - python3-pytest
-    - python3-pretend
+    - python3-pytest-subtests
+    environment:
+      PYTHONPATH: "{{ srcdir }}/vectors"
     tests:
     - remove_hypothesis:
         # remove tests that depend on python3-hypothesis package
@@ -27,6 +29,9 @@
         # scrypt tests require more memory than available
         dir: "source"
         run: rm -f tests/hazmat/primitives/test_scrypt.py
+    - patch_conftest:
+        dir: "source"
+        run: "cat ../conftest-skipper.py  >> tests/conftest.py"
     # tests take some time, split up to avoid CI timeouts.
     - unittests-basic:
         dir: "source"