test: pin invalid timezone error on EncounterRecencyTransformer

CHANGELOG.md

@@ -6,6 +6,9 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 ## [Unreleased]
 
 ### Added
+- Regression test that an invalid `timezone=` on
+  `EncounterRecencyTransformer` raises `KeyError` naming the zone, not
+  `TypeError("Already tz-aware")`. Closes #204.
 - Tests for `MovesManagementClassifier` now fit a named DataFrame and an
   array so `feature_names_in_` is both recorded and absent on the paths
   sklearn specifies. Closes #200.

CONTRIBUTORS.md

@@ -10,6 +10,10 @@ contribution. Code, docs, tests, and review all count.
 
 ## Contributors
 
+- **Harsh Raj Singhania** ([@HarshRajSinghania](https://github.com/HarshRajSinghania)):
+  added a regression test so an invalid timezone on
+  `EncounterRecencyTransformer` raises `KeyError` naming the zone (closes
+  [#204](https://github.com/PhilanthroPy-Project/PhilanthroPy/issues/204)).
 - **Leyn.cx** ([@laichouchi](https://github.com/laichouchi)): fixed Windows
   drive-letter paths being rejected as URI schemes (closes #217).
 

tests/test_encounter_timezone.py

@@ -5,6 +5,8 @@
 
 import os
 
+import pytest
+
 import numpy as np
 import pandas as pd
 
@@ -73,3 +75,18 @@ def test_naive_dates_with_a_tz_aware_reference_date():
 
     assert out.shape == (2, 3)
     np.testing.assert_allclose(out[:, 0], [364.0, 213.0])
+
+def test_invalid_timezone_raises_keyerror_naming_the_zone():
+    """Invalid timezone names must surface as a lookup error, not TypeError.
+
+    pandas 2 (pytz) and pandas 3 (zoneinfo) raise different concrete types,
+    but both subclass KeyError and include the zone name. The pre-#202
+    fallback turned this into TypeError('Already tz-aware').
+    """
+    X = pd.DataFrame({"last_encounter_date": ["2023-01-01", "2023-06-01"]})
+    t = EncounterRecencyTransformer(
+        reference_date="2023-12-31", timezone="Not/AZone"
+    )
+    with pytest.raises(KeyError, match="Not/AZone") as excinfo:
+        t.fit_transform(X)
+    assert "Already tz-aware" not in str(excinfo.value)