Fix reductions on boolean reductions. (#104)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: dcherian

flox/core.py

@@ -1465,6 +1465,8 @@ def groupby_reduce(
 
     if not is_duck_array(array):
         array = np.asarray(array)
+    array = array.astype(int) if np.issubdtype(array.dtype, bool) else array
+
     if isinstance(isbin, bool):
         isbin = (isbin,) * len(by)
     if expected_groups is None:

tests/test_core.py

@@ -830,6 +830,17 @@ def test_datetime_binning():
     assert_equal(group_idx, expected)
 
 
+@pytest.mark.parametrize("func", ALL_FUNCS)
+def test_bool_reductions(func, engine):
+    if "arg" in func and engine == "flox":
+        pytest.skip()
+    groups = np.array([1, 1, 1])
+    data = np.array([True, True, False])
+    expected = np.expand_dims(getattr(np, func)(data), -1)
+    actual, _ = groupby_reduce(data, groups, func=func, engine=engine)
+    assert_equal(expected, actual)
+
+
 @requires_dask
 def test_map_reduce_blockwise_mixed():
     t = pd.date_range("2000-01-01", "2000-12-31", freq="D").to_series()