improved error message for index/time_index being same column in norm…

docs/source/changelog.rst

@@ -10,6 +10,7 @@ Changelog
         * Support custom variable types (:pr:`571`)
     * Fixes
         * Normalize_entity specifies error when 'make_time_index' is an invalid string (:pr:`550`)
+        * Improved error message for index/time_index being the same column in normalize_entity and entity_from_dataframe (:pr:`583`)
         * Removed all mentions of allow_where (:pr:`587`, :pr:`588`)
         * Removed unused variable in normalize entity (:pr:`589`)
     * Changes

featuretools/entityset/entityset.py

@@ -646,6 +646,10 @@ def entity_from_dataframe(self,
 
         """
         variable_types = variable_types or {}
+
+        if time_index is not None and time_index == index:
+            raise ValueError("time_index and index cannot be the same value, %s" % (time_index))
+
         entity = Entity(
             entity_id,
             dataframe,
@@ -763,6 +767,9 @@ def normalize_entity(self, base_entity_id, new_entity_id, index,
             new_entity_time_index = None
             already_sorted = False
 
+        if new_entity_time_index is not None and new_entity_time_index == index:
+            raise ValueError("time_index and index cannot be the same value, %s" % (new_entity_time_index))
+
         selected_variables = [index] +\
             [v for v in additional_variables] +\
             [v for v in copy_variables]

featuretools/tests/entityset_tests/test_es.py

@@ -982,3 +982,28 @@ def _slice_for(es, filter_eid, time_last=None):
                                     index_eid='customers',
                                     instances=[0],
                                     time_last=time_last)
+
+
+def test_same_index_values():
+    transactions_df = pd.DataFrame({"id": [1, 2, 3, 4, 5, 6],
+                                    "transaction_time": pd.date_range(start="10:00", periods=6, freq="10s"),
+                                    "first_entity_time": [1, 2, 3, 5, 6, 6]})
+    es = ft.EntitySet("example")
+
+    error_text = "time_index and index cannot be the same value"
+    with pytest.raises(ValueError, match=error_text):
+        es.entity_from_dataframe(entity_id="entity",
+                                 index="id",
+                                 time_index="id",
+                                 dataframe=transactions_df)
+
+    es.entity_from_dataframe(entity_id="entity",
+                             index="id",
+                             time_index="transaction_time",
+                             dataframe=transactions_df)
+
+    with pytest.raises(ValueError, match=error_text):
+        es.normalize_entity(base_entity_id="entity",
+                            new_entity_id="new_entity",
+                            index="first_entity_time",
+                            make_time_index=True)