MAINT: Make OpenMM optional again

.github/workflows/ci.yaml

@@ -74,7 +74,7 @@ jobs:
         micromamba install openmm -c conda-forge
 
     - name: Uninstall OpenMM
-      if: ${{ matrix.openmm == false && matrix.openeye == true }}
+      if: ${{ matrix.openmm == false }}
       run: |
         micromamba remove openmm mdtraj
         # Removing mBuild also removes some leaves, need to re-install them

openff/interchange/_tests/__init__.py

@@ -13,6 +13,7 @@
     RDKitToolkitWrapper,
 )
 from openff.utilities import get_data_file_path
+from openff.utilities.exceptions import MissingOptionalDependencyError
 from openff.utilities.utilities import has_executable, has_package
 
 from openff.interchange import Interchange
@@ -38,6 +39,37 @@
     reason="Test requires OE toolkit",
 )
 
+HAS_OPENMM = has_package("openmm")
+HAS_GROMACS = _find_gromacs_executable() is not None
+HAS_LAMMPS = has_package("lammps")
+HAS_SANDER = has_executable("sander")
+
+try:
+    import foyer
+
+    assert "openff/interchange" not in foyer.__file__
+    HAS_FOYER = True
+except (ModuleNotFoundError, AssertionError):
+    HAS_FOYER = False
+
+needs_openmm = pytest.mark.skipif(not HAS_OPENMM, reason="Needs OpenMM")
+needs_gmx = pytest.mark.skipif(not HAS_GROMACS, reason="Needs GROMACS")
+needs_not_gmx = pytest.mark.skipif(
+    HAS_GROMACS,
+    reason="Needs GROMACS to NOT be installed",
+)
+needs_lmp = pytest.mark.skipif(not HAS_LAMMPS, reason="Needs LAMMPS")
+needs_not_lmp = pytest.mark.skipif(
+    HAS_LAMMPS,
+    reason="Needs LAMMPS to NOT be installed",
+)
+needs_sander = pytest.mark.skipif(not HAS_SANDER, reason="Needs sander")
+needs_not_sander = pytest.mark.skipif(
+    HAS_SANDER,
+    reason="sander needs to NOT be installed",
+)
+needs_foyer = pytest.mark.skipif(not HAS_FOYER, reason="Needs foyer")
+
 
 _rng = numpy.random.default_rng(12345)
 
@@ -96,33 +128,15 @@ def from_mapped_smiles(self, smiles, name="", **kwargs):
 
 def get_protein(name: str) -> Molecule:
     """Get a protein from openff/toolkit/data/proteins based on PDB name."""
-    return Topology.from_pdb(
-        get_data_file_path(
-            relative_path=f"proteins/{name}.pdb",
-            package_name="openff.toolkit",
-        ),
-    ).molecule(0)
-
-
-HAS_GROMACS = _find_gromacs_executable() is not None
-HAS_LAMMPS = has_package("lammps")
-HAS_SANDER = has_executable("sander")
-
-needs_gmx = pytest.mark.skipif(not HAS_GROMACS, reason="Needs GROMACS")
-needs_not_gmx = pytest.mark.skipif(
-    HAS_GROMACS,
-    reason="Needs GROMACS to NOT be installed",
-)
-needs_lmp = pytest.mark.skipif(not HAS_LAMMPS, reason="Needs LAMMPS")
-needs_not_lmp = pytest.mark.skipif(
-    HAS_LAMMPS,
-    reason="Needs LAMMPS to NOT be installed",
-)
-needs_sander = pytest.mark.skipif(not HAS_SANDER, reason="Needs sander")
-needs_not_sander = pytest.mark.skipif(
-    HAS_SANDER,
-    reason="sander needs to NOT be installed",
-)
+    try:
+        return Topology.from_pdb(
+            get_data_file_path(
+                relative_path=f"proteins/{name}.pdb",
+                package_name="openff.toolkit",
+            ),
+        ).molecule(0)
+    except (ModuleNotFoundError, MissingOptionalDependencyError):
+        return pytest.skip("Test requires OpenMM for protein loading")
 
 
 def shuffle_topology(

openff/interchange/_tests/energy_tests/components/test_mdconfig.py

@@ -1,12 +1,12 @@
 from openff.units import Quantity, unit
 
-from openff.interchange._tests import MoleculeWithConformer, needs_gmx, needs_lmp
+from openff.interchange._tests import MoleculeWithConformer, needs_gmx, needs_openmm
 from openff.interchange.drivers import get_gromacs_energies, get_openmm_energies
 
 
 class TestLJPME:
     @needs_gmx
-    @needs_lmp
+    @needs_openmm
     def test_ljpme(self, sage):
         sage["vdW"].periodic_method = "Ewald3D"
 

openff/interchange/_tests/energy_tests/test_energies.py

@@ -9,8 +9,10 @@
     HAS_LAMMPS,
     MoleculeWithConformer,
     get_test_file_path,
+    needs_foyer,
     needs_gmx,
     needs_lmp,
+    needs_openmm,
 )
 from openff.interchange.constants import kj_mol
 from openff.interchange.drivers import get_openmm_energies
@@ -99,7 +101,7 @@ def test_energies_single_mol(self, constrained, sage, sage_unconstrained, mol_sm
             lmp_energies.compare(other_energies, tolerances)
 
     @needs_gmx
-    @skip_if_missing("foyer")
+    @needs_foyer
     @skip_if_missing("mbuild")
     def test_process_rb_torsions(self, oplsaa):
         """Test that the GROMACS driver reports Ryckaert-Bellemans torsions"""
@@ -194,6 +196,7 @@ def test_cutoff_electrostatics(self):
         ],
     )
     @needs_gmx
+    @needs_openmm
     @pytest.mark.slow
     def test_interpolated_parameters(self, smi):
         xml_ff_bo_all_heavy_bonds = """<?xml version='1.0' encoding='ASCII'?>
@@ -240,6 +243,7 @@ def test_interpolated_parameters(self, smi):
                 )
 
     @needs_gmx
+    @needs_openmm
     def test_rb_torsion_energies(self, monkeypatch):
         monkeypatch.setenv("INTERCHANGE_EXPERIMENTAL", "1")
 

openff/interchange/_tests/test_issues.py

@@ -9,7 +9,7 @@
 from openff.utilities import get_data_file_path, skip_if_missing
 
 from openff.interchange import Interchange
-from openff.interchange._tests import MoleculeWithConformer, shuffle_topology
+from openff.interchange._tests import MoleculeWithConformer, needs_openmm, shuffle_topology
 from openff.interchange.components._packmol import pack_box
 from openff.interchange.drivers import get_openmm_energies
 
@@ -26,6 +26,7 @@ def test_issue_723():
 
 
 @pytest.mark.parametrize("pack", [True, False])
+@needs_openmm
 def test_issue_1022(pack):
     topology = Topology.from_molecules(
         [

openff/interchange/_tests/unit_tests/components/test_foyer.py

@@ -7,7 +7,7 @@
 from openff.utilities.testing import has_package, skip_if_missing
 
 from openff.interchange import Interchange
-from openff.interchange._tests import HAS_GROMACS, get_test_files_dir_path, needs_gmx
+from openff.interchange._tests import HAS_GROMACS, get_test_files_dir_path, needs_foyer, needs_gmx
 from openff.interchange.components.potentials import Potential
 from openff.interchange.constants import kj_mol
 from openff.interchange.drivers import get_openmm_energies
@@ -27,7 +27,7 @@
     )
 
 
-@skip_if_missing("foyer")
+@needs_foyer
 class TestFoyer:
     @pytest.fixture(scope="session")
     def oplsaa(self):

openff/interchange/_tests/unit_tests/components/test_interchange.py

@@ -212,6 +212,8 @@ def test_to_openmm_simulation(
         )
 
     def test_add_barostat(self, sage, default_integrator, default_barostat):
+        pytest.importorskip("openmm")
+
         import openmm
         import openmm.unit
 

openff/interchange/_tests/unit_tests/interop/amber/export/test_export.py

@@ -32,6 +32,8 @@
 )
 def test_atom_names_with_padding(molecule):
     # pytest processes fixtures before the decorator can be applied
+    pytest.importorskip("openmm")
+
     if molecule.endswith(".pdb"):
         molecule = Topology.from_pdb(
             file_path=get_test_file_path(molecule).as_posix(),

openff/interchange/_tests/unit_tests/interop/lammps/export/test_lammps.py

@@ -39,6 +39,8 @@ def test_to_lammps_single_mols(
         TODO: Tighten tolerances
         TODO: Test periodic and non-periodic
         """
+        pytest.importorskip("openmm")
+
         mol = MoleculeWithConformer.from_smiles(mol)
         mol.conformers[0] -= numpy.min(mol.conformers[0], axis=0)
         top = Topology.from_molecules(n_mols * [mol])

openff/interchange/_tests/unit_tests/interop/openmm/_import/test_compat.py

@@ -5,15 +5,16 @@
 import pytest
 from openff.toolkit import Molecule, Quantity
 
+from openff.interchange._tests import needs_openmm
 from openff.interchange.exceptions import UnsupportedImportError
 from openff.interchange.interop.openmm._import import from_openmm
 from openff.interchange.warnings import MissingPositionsWarning
 
 
 class TestUnsupportedCases:
     @pytest.mark.filterwarnings("ignore:.*are you sure you don't want to pass positions")
-    def test_error_topology_mismatch(self, monkeypatch, sage_unconstrained, ethanol):
-        monkeypatch.setenv("INTERCHANGE_EXPERIMENTAL", "1")
+    def test_error_topology_mismatch(self, sage_unconstrained, ethanol):
+        pytest.importorskip("openmm")
 
         topology = ethanol.to_topology()
         topology.box_vectors = Quantity([4, 4, 4], "nanometer")
@@ -38,9 +39,8 @@ def test_error_topology_mismatch(self, monkeypatch, sage_unconstrained, ethanol)
                 topology=other_topology.to_openmm(),
             )
 
-    def test_found_virtual_sites(self, monkeypatch, tip4p, water):
-        monkeypatch.setenv("INTERCHANGE_EXPERIMENTAL", "1")
-
+    @needs_openmm
+    def test_found_virtual_sites(self, tip4p, water):
         topology = water.to_topology()
         topology.box_vectors = Quantity([4, 4, 4], "nanometer")
 
@@ -55,9 +55,8 @@ def test_found_virtual_sites(self, monkeypatch, tip4p, water):
                 topology=topology.to_openmm(),
             )
 
-    def test_missing_positions_warning(self, monkeypatch, sage, water):
-        monkeypatch.setenv("INTERCHANGE_EXPERIMENTAL", "1")
-
+    @needs_openmm
+    def test_missing_positions_warning(self, sage, water):
         topology = water.to_topology()
         topology.box_vectors = Quantity([4, 4, 4], "nanometer")
 

openff/interchange/_tests/unit_tests/interop/openmm/test_hmr.py

@@ -3,6 +3,7 @@
 import pytest
 from openff.toolkit import Molecule, unit
 
+from openff.interchange._tests import needs_openmm
 from openff.interchange.exceptions import NegativeMassError, UnsupportedExportError
 
 
@@ -80,6 +81,7 @@ def test_mass_is_positive(sage):
         sage.create_interchange(Molecule.from_smiles("C").to_topology()).to_openmm(hydrogen_mass=5.0)
 
 
+@needs_openmm
 def test_virtual_sites_unsupported(tip4p, water):
     with pytest.raises(UnsupportedExportError, match="with virtual sites"):
         tip4p.create_interchange(water.to_topology()).to_openmm(hydrogen_mass=2.0)

openff/interchange/_tests/unit_tests/interop/openmm/test_topology.py

@@ -42,6 +42,8 @@ def test_each_molecule_with_virtual_sites_has_its_own_funnky_virtual_site_residu
     tip5p,
     water,
 ):
+    pytest.importorskip("openmm")
+
     topology = Topology.from_molecules([water, water])
 
     for index, molecule in enumerate(topology.molecules):

openff/interchange/_tests/unit_tests/interop/test_virtual_sites.py

@@ -6,7 +6,7 @@
 import pytest
 from openff.toolkit import ForceField, Quantity, unit
 
-from openff.interchange._tests import MoleculeWithConformer
+from openff.interchange._tests import MoleculeWithConformer, needs_openmm
 from openff.interchange.exceptions import MissingVirtualSitesError
 from openff.interchange.interop._virtual_sites import get_positions_with_virtual_sites
 
@@ -37,6 +37,7 @@ def test_nonzero_positions(tip4p_interchange):
     )
 
 
+@needs_openmm
 def test_collate_virtual_site_positions(tip4p, water_dimer):
     out = tip4p.create_interchange(water_dimer)
 

openff/interchange/_tests/unit_tests/operations/minimize/test_openmm.py

@@ -1,8 +1,8 @@
+import pytest
 from openff.utilities import has_package, skip_if_missing
 
 if has_package("openmm"):
     import numpy
-    import pytest
     from openff.toolkit import Molecule
 
     from openff.interchange._tests import MoleculeWithConformer

openff/interchange/_tests/unit_tests/smirnoff/test_create.py

@@ -4,7 +4,7 @@
 from openff.utilities.testing import skip_if_missing
 
 from openff.interchange import Interchange
-from openff.interchange._tests import get_test_file_path
+from openff.interchange._tests import get_test_file_path, needs_openmm
 from openff.interchange.constants import kcal_mol, kcal_mol_a2
 from openff.interchange.exceptions import (
     PresetChargesError,
@@ -65,6 +65,7 @@ def test_infer_positions(self, sage, ethanol):
             3,
         )
 
+    @needs_openmm
     def test_cosmetic_attributes(self):
         from openff.toolkit._tests.test_forcefield import xml_ff_w_cosmetic_elements
 

openff/interchange/components/interchange.py

@@ -43,7 +43,11 @@
 from openff.interchange.warnings import InterchangeDeprecationWarning
 
 if has_package("foyer"):
-    from foyer.forcefield import Forcefield as FoyerForcefield
+    try:
+        from foyer.forcefield import Forcefield as FoyerForcefield
+    except ModuleNotFoundError:
+        # case of openff/interchange/foyer/ being detected as the real package
+        pass
 if has_package("nglview"):
     import nglview
 

openff/interchange/foyer/_base.py

@@ -8,8 +8,12 @@
 from openff.interchange.models import PotentialKey, TopologyKey
 
 if has_package("foyer"):
-    from foyer.exceptions import MissingForceError, MissingParametersError
-    from foyer.forcefield import Forcefield
+    try:
+        from foyer.exceptions import MissingForceError, MissingParametersError
+        from foyer.forcefield import Forcefield
+    except ModuleNotFoundError:
+        # case of openff/interchange/foyer/ being detected as the real package
+        pass
 
 
 # Is this the safest way to achieve PotentialKey id separation?

openff/interchange/interop/openmm/_import/compat.py

@@ -1,13 +1,18 @@
-import openmm
-import openmm.app
+from typing import TYPE_CHECKING, Union
+
 from openff.toolkit import Topology
+from openff.utilities.utilities import has_package
 
 from openff.interchange.exceptions import UnsupportedImportError
 
+if has_package("openmm") or TYPE_CHECKING:
+    import openmm
+    import openmm.app
+
 
 def _check_compatible_inputs(
-    system: openmm.System,
-    topology: openmm.app.Topology | Topology | None,
+    system: "openmm.System",
+    topology: Union["openmm.app.Topology", Topology, None],
 ):
     """Check that inputs are compatible and supported."""
     for index in range(system.getNumParticles()):