Make jax optional in testing suite

pyproject.toml

@@ -70,7 +70,8 @@ lines-between-types = 1
 [tool.ruff.lint.per-file-ignores]
 'tests/*.py' = [
   'F841', # Unused variable warning for test files -- common in pymc model declarations
-  'D106'  # Missing docstring for public method -- unittest test subclasses don't need docstrings
+  'D106',  # Missing docstring for public method -- unittest test subclasses don't need docstrings
+  'E402'  # Import at top, not respected when pytest.importorskip is required
 ]
 'tests/statespace/*.py' =  [
   'F401', # Unused import warning for test files -- this check removes imports of fixtures

tests/test_blackjax_smc.py

@@ -11,7 +11,6 @@
 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
-import jax
 import numpy as np
 import pymc as pm
 import pytensor.tensor as pt
@@ -21,6 +20,9 @@
 from numpy import dtype
 from xarray.core.utils import Frozen
 
+jax = pytest.importorskip("jax")
+pytest.importorskip("blackjax")
+
 from pymc_experimental.inference.smc.sampling import (
     arviz_from_particles,
     blackjax_particles_from_pymc_population,