Add and test doctest-modules

pyproject.toml

@@ -116,7 +116,7 @@ versionfile_build = "pytensor/_version.py"
 tag_prefix = "rel-"
 
 [tool.pytest]
-addopts = "--durations=50"
+addopts = "--durations=50 --doctest-modules"
 testpaths = "tests/"
 
 [tool.ruff]

pytensor/gradient.py

@@ -2086,13 +2086,13 @@ def hessian_vector_product(cost, wrt, p, **grad_kwargs):
 
         from pytensor import function
         from pytensor.tensor import vector
-        from pytensor.gradient import jacobian, hessian_vector_product
+        from pytensor.gradient import grad, hessian_vector_product
 
         x = vector('x')
         p = vector('p')
 
         rosen = (100 * (x[1:] - x[:-1] ** 2) ** 2 + (1 - x[:-1]) ** 2).sum()
-        rosen_jac = jacobian(rosen, x)
+        rosen_jac = grad(rosen, x)
         rosen_hessp = hessian_vector_product(rosen, x, p)
 
         rosen_fn = function([x], rosen)
@@ -2107,6 +2107,7 @@ def hessian_vector_product(cost, wrt, p, **grad_kwargs):
             hessp=rosen_hessp_fn,
             options={"xtol": 1e-8},
         )
+        assert 0
         assert res.success
         np.testing.assert_allclose(res.x, np.ones_like(x0))