From b5639f00a99e48eec169b478d782308806b95d33 Mon Sep 17 00:00:00 2001
From: "Matthew W. Thompson" <mattwthompson@protonmail.com>
Date: Thu, 16 Jan 2025 10:02:26 -0600
Subject: [PATCH] MAINT: Only test with OpenMM

---
 .github/workflows/ci.yaml                    |  2 +-
 devtools/conda-envs/examples_env.yaml        |  1 -
 openff/interchange/components/interchange.py | 14 +++++++++-----
 openff/interchange/foyer/_base.py            |  7 ++++++-
 openff/interchange/foyer/_create.py          |  5 ++++-
 openff/interchange/foyer/_nonbonded.py       |  5 ++++-
 6 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index d13978f1f..82f4f81af 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -33,10 +33,10 @@ jobs:
           - false
         openmm:
           - true
-          - false
 
     env:
       OE_LICENSE: ${{ github.workspace }}/oe_license.txt
+      COV: --cov=openff/interchange --cov-report=xml --cov-config=pyproject.toml --cov-append
 
     steps:
     - uses: actions/checkout@v4
diff --git a/devtools/conda-envs/examples_env.yaml b/devtools/conda-envs/examples_env.yaml
index cd51766f5..00d197cc6 100644
--- a/devtools/conda-envs/examples_env.yaml
+++ b/devtools/conda-envs/examples_env.yaml
@@ -30,7 +30,6 @@ dependencies:
   - mdtraj
   - pytest
   - pytest-xdist
-  - pytest-cov
   - nbval
   # Examples
   - openmmforcefields
diff --git a/openff/interchange/components/interchange.py b/openff/interchange/components/interchange.py
index c07575049..f81c2986f 100644
--- a/openff/interchange/components/interchange.py
+++ b/openff/interchange/components/interchange.py
@@ -49,7 +49,11 @@
     from openff.toolkit import ForceField
 
     if has_package("foyer"):
-        from foyer 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
 
@@ -836,13 +840,13 @@ def from_foyer(
 
             >>> from openff.interchange import Interchange
             >>> from openff.toolkit import Molecule, Topology
-            >>> from foyer import Forcefield
+            >>> from foyer.forcefield import Forcefield  # doctest: +SKIP
             >>> mol = Molecule.from_smiles("CC")
             >>> mol.generate_conformers(n_conformers=1)
             >>> top = Topology.from_molecules([mol])
-            >>> oplsaa = Forcefield(name="oplsaa")
-            >>> interchange = Interchange.from_foyer(topology=top, force_field=oplsaa)
-            >>> interchange
+            >>> oplsaa = Forcefield(name="oplsaa")  # doctest: +SKIP
+            >>> interchange = Interchange.from_foyer(topology=top, force_field=oplsaa)  # doctest: +SKIP
+            >>> interchange  # doctest: +SKIP
             Interchange with 8 collections, non-periodic topology with 8 atoms.
 
         """
diff --git a/openff/interchange/foyer/_base.py b/openff/interchange/foyer/_base.py
index c4b8fdd94..83e26d45a 100644
--- a/openff/interchange/foyer/_base.py
+++ b/openff/interchange/foyer/_base.py
@@ -3,12 +3,17 @@
 from typing import TYPE_CHECKING
 
 from openff.toolkit import Topology
+from openff.utilities import has_package
 
 from openff.interchange.components.potentials import Collection, Potential
 from openff.interchange.models import PotentialKey, TopologyKey
 
 if TYPE_CHECKING:
-    from foyer import Forcefield
+    if has_package("foyer"):
+        try:
+            from foyer.forcefield import Forcefield
+        except ModuleNotFoundError:
+            pass
 
 
 # Is this the safest way to achieve PotentialKey id separation?
diff --git a/openff/interchange/foyer/_create.py b/openff/interchange/foyer/_create.py
index 5d4600eff..baacf57c9 100644
--- a/openff/interchange/foyer/_create.py
+++ b/openff/interchange/foyer/_create.py
@@ -22,7 +22,10 @@
 from openff.interchange.models import TopologyKey
 
 if has_package("foyer"):
-    from foyer.forcefield import Forcefield
+    try:
+        from foyer.forcefield import Forcefield
+    except ModuleNotFoundError:
+        pass
 
 _CollectionAlias = type[Collection]
 
diff --git a/openff/interchange/foyer/_nonbonded.py b/openff/interchange/foyer/_nonbonded.py
index 947eb58ff..ff1af5e7b 100644
--- a/openff/interchange/foyer/_nonbonded.py
+++ b/openff/interchange/foyer/_nonbonded.py
@@ -11,7 +11,10 @@
 from openff.interchange.models import PotentialKey, TopologyKey
 
 if has_package("foyer"):
-    from foyer import Forcefield
+    try:
+        from foyer.forcefield import Forcefield
+    except ModuleNotFoundError:
+        pass
 
 
 class FoyerVDWHandler(vdWCollection):