add unit test for _scale_charges, remove import from init func in utils

hoomd_organics/tests/base/test_system.py

@@ -242,3 +242,25 @@ def test_lattice_molecule(self, benzene_molecule):
         assert len(system.hoomd_forcefield) > 0
         assert system.n_particles == system.hoomd_snapshot.particles.N
         assert system.reference_values.keys() == {"energy", "length", "mass"}
+
+    def test_scale_charges(self, pps):
+        pps_mol = pps(num_mols=5, lengths=5)
+        no_scale = Pack(
+            molecules=pps_mol,
+            density=0.5,
+            r_cut=2.4,
+            force_field=OPLS_AA_PPS(),
+            auto_scale=True,
+            scale_charges=False,
+        )
+
+        with_scale = Pack(
+            molecules=pps_mol,
+            density=0.5,
+            r_cut=2.4,
+            force_field=OPLS_AA_PPS(),
+            auto_scale=True,
+            scale_charges=True,
+        )
+        assert abs(no_scale.net_charge.value) > abs(with_scale.net_charge.value)
+        assert np.allclose(0, with_scale.net_charge.value, atol=1e-30)

hoomd_organics/tests/base_test.py

@@ -175,6 +175,26 @@ def __init__(self, lengths, num_mols, **kwargs):
 
         return _PolyEthylene
 
+    @pytest.fixture()
+    def pps(self, pps_smiles):
+        class _PPS(Polymer):
+            def __init__(self, lengths, num_mols, **kwargs):
+                smiles = pps_smiles
+                bond_indices = [7, 10]
+                bond_length = 0.176
+                bond_orientation = [[0, 0, 1], [0, 0, -1]]
+                super().__init__(
+                    lengths=lengths,
+                    num_mols=num_mols,
+                    smiles=smiles,
+                    bond_indices=bond_indices,
+                    bond_length=bond_length,
+                    bond_orientation=bond_orientation,
+                    **kwargs
+                )
+
+        return _PPS
+
     @pytest.fixture()
     def polyDME(self, dimethylether_smiles):
         class _PolyDME(Polymer):
@@ -219,14 +239,3 @@ def polyethylene_system(self, polyethylene):
             remove_hydrogens=True,
         )
         return system
-
-    # @pytest.fixture()
-    # def ua_polyethylene_system(self):
-    #     system = Pack(
-    #             molecule=PolyEthylene,
-    #             n_mols=5,
-    #             mol_kwargs={"length": 5},
-    #             density=0.5
-    #     )
-    #     system.apply_forcefield(forcefield=GAFF(), remove_hydrogens=True)
-    #     return system

hoomd_organics/utils/__init__.py

@@ -1,4 +1,4 @@
 from .actions import *
 from .base_types import FF_Types
 from .ff_utils import xml_to_gmso_ff
-from .utils import check_return_iterable, scale_charges
+from .utils import check_return_iterable