Adding a test ton ensure an exception is raised when len(time_range) != 2

Author: JeanVanDyk

causalpy/experiments/change_point_detection.py

@@ -96,7 +96,7 @@
 from matplotlib import pyplot as plt
 from patsy import dmatrices
 
-from causalpy.custom_exceptions import BadIndexException, ModelException
+from causalpy.custom_exceptions import BadIndexException, DataException, ModelException
 from causalpy.experiments.base import BaseExperiment
 from causalpy.plot_utils import get_hdi_to_df, plot_xY
 from causalpy.pymc_models import PyMCModel
@@ -259,7 +259,7 @@ def input_validation(self, data, time_range, model):
         if not hasattr(model, "set_time_range"):
             raise ModelException("Provided model must have a 'set_time_range' method")
         if time_range is not None and len(time_range) != 2:
-            raise BadIndexException(
+            raise DataException(
                 "Provided time_range must be of length 2 : (start, end)"
             )
         if isinstance(data.index, pd.DatetimeIndex) and not (

causalpy/tests/test_integration_pymc_examples.py

@@ -433,6 +433,20 @@ def test_cp_covid():
         )
     assert "Provided model must have a 'set_time_range' method" in str(exc_info.value)
 
+    # Assert that we correctfully raise a DataException if
+    # - time_range is not None
+    # - and len(time_range) is not 2
+    with pytest.raises(cp.custom_exceptions.DataExveption) as exc_info:
+        cp.ChangePointDetection(
+            df,
+            time_range=[0, 0, 0],
+            formula="standardize(deaths) ~ 0 + t + C(month) + standardize(temp)",  # noqa E501
+            model=cp.pymc_models.LinearRegression(sample_kwargs=sample_kwargs),
+        )
+    assert "Provided time_range must be of length 2 : (start, end)" in str(
+        exc_info.value
+    )
+
     result = cp.ChangePointDetection(
         df,
         time_range=time_range,