BUG: BooleanArray.value_counts dropna

Closes pandas-dev#30685

Author: TomAugspurger

pandas/core/arrays/boolean.py

@@ -628,7 +628,8 @@ def value_counts(self, dropna=True):
             # w/o passing the dtype
             array = np.append(array, [self._mask.sum()])
             index = Index(
-                np.concatenate([index, np.array([np.nan], dtype=object)]), dtype=object
+                np.concatenate([index, np.array([self.dtype.na_value], dtype=object)]),
+                dtype=object,
             )
 
         return Series(array, index=index)

pandas/tests/arrays/test_boolean.py

@@ -856,3 +856,10 @@ def test_arrow_roundtrip():
     result = table.to_pandas()
     assert isinstance(result["a"].dtype, pd.BooleanDtype)
     tm.assert_frame_equal(result, df)
+
+
+def test_value_counts_na():
+    arr = pd.array([True, False, pd.NA], dtype="boolean")
+    result = arr.value_counts(dropna=False)
+    expected = pd.Series([1, 1, 1], index=[True, False, pd.NA])
+    tm.assert_series_equal(result, expected)