Add input validation to team_fielding_bref

pybaseball/team_fielding.py

@@ -32,7 +32,12 @@ def team_fielding_bref(team: str, start_season: int, end_season: Optional[int]=N
         )
     if end_season is None:
         end_season = start_season
+    if end_season < start_season:
+        raise ValueError(
+            "end_season must be greater than or equal to start_season."
+        )
 
+    team = team.upper()
     url = "https://www.baseball-reference.com/teams/{}".format(team)
 
     raw_data = []

tests/pybaseball/test_team_fielding.py

@@ -25,3 +25,12 @@ def test_team_fielding(response_get_monkeypatch: Callable, sample_html: str, sam
     team_fielding_result = team_fielding(season).reset_index(drop=True)
 
     pd.testing.assert_frame_equal(team_fielding_result, sample_processed_result, check_dtype=False)
+
+
+def test_team_fielding_bref_invalid_season_range() -> None:
+    # Regression test for #462: an end_season earlier than start_season should
+    # raise a clear ValueError before any network request is made.
+    from pybaseball.team_fielding import team_fielding_bref
+
+    with pytest.raises(ValueError):
+        team_fielding_bref('NYY', 2019, 2018)