[Chore] Package Export, Blanks for fields, Styling (#421)

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#421

tests/test_reaction_model.py

@@ -1,6 +1,7 @@
 from django.conf import settings as s
 from django.test import TestCase, override_settings
 
+from epdb.exceptions import InvalidSMILESException
 from epdb.logic import PackageManager
 from epdb.models import Compound, User, Reaction, Rule
 
@@ -163,7 +164,7 @@ class ReactionTest(TestCase):
         self.assertEqual(len(self.package.reactions), 1)
 
     def test_wrong_smiles(self):
-        with self.assertRaises(ValueError):
+        with self.assertRaises(InvalidSMILESException):
             _ = Reaction.create(
                 package=self.package,
                 name="Eawag BBD reaction r0001",