Update test_timeseries_model.py

Author: phumthep

src/test_pownet/test_stochastic/test_timeseries_model.py

@@ -4,6 +4,13 @@
 import pandas as pd
 from pownet.stochastic import timeseries_model
 
+# Skip this test if the user has not installed pmdarima package
+try:
+    import pmdarima
+except ImportError:
+    pmdarima = None
+    raise unittest.SkipTest("pmdarima is not installed, skipping tests.")
+
 
 class ConcreteTimeSeriesModel(timeseries_model.TimeSeriesModel):
     """A concrete implementation for testing the abstract base class."""