Add missing test guards.

Author: lohedges

tests/Align/test_align.py

@@ -697,6 +697,7 @@ def test_ion_merge(system):
     assert coords0 == water_coords
 
 
+@pytest.mark.skipif(has_amber is False, reason="Requires AMBER to be installed.")
 @pytest.mark.skipif(has_openff is False, reason="Requires OpenFF to be installed.")
 @pytest.mark.parametrize(
     "ligands, mapping",

tests/Sandpit/Exscientia/Align/test_align.py

@@ -752,6 +752,9 @@ def test_ion_merge():
     assert coords0 == water_coords
 
 
+@pytest.mark.skipif(
+    has_antechamber is False, reason="Requires AnteChamber to be installed."
+)
 @pytest.mark.skipif(has_openff is False, reason="Requires OpenFF to be installed.")
 @pytest.mark.parametrize(
     "ligands, mapping",