add test structure

tests/test_model.py

@@ -47,6 +47,7 @@
 from pymc.logprob.basic import conditional_logp, transformed_conditional_logp
 from pymc.logprob.transforms import IntervalTransform
 from pymc.model import Point, ValueGradFunction, modelcontext
+from pymc.model_graph import model_to_graphviz, model_to_networkx
 from pymc.util import _FutureWarningValidatingScratchpad
 from pymc.variational.minibatch_rv import MinibatchRandomVariable
 from tests.models import simple_model
@@ -1653,3 +1654,26 @@ def test_model_logp_fast_compile():
 
     with pytensor.config.change_flags(mode="FAST_COMPILE"):
         assert m.point_logps() == {"a": -1.5}
+
+
+class TestModelGraphs:
+    @staticmethod
+    def school_model() -> pm.Model:
+        J = 8
+        y = np.array([28, 8, -3, 7, -1, 1, 18, 12])
+        sigma = np.array([15, 10, 16, 11, 9, 11, 10, 18])
+        with pm.Model() as schools:
+            eta = pm.Normal("eta", 0, 1, shape=J)
+            mu = pm.Normal("mu", 0, sigma=1e6)
+            tau = pm.HalfCauchy("tau", 25)
+            theta = mu + tau * eta
+            obs = pm.Normal("obs", theta, sigma=sigma, observed=y)
+        return schools
+
+    def test_graphviz(self) -> None:
+        model = self.school_model()
+        assert model.graphviz()
+
+    def test_networkx(self) -> None:
+        model = self.school_model()
+        model_to_networkx(model=model) == model.networkx()