DEPR: pandas.types.concat.union_categoricals in favor of pandas.api.type.union_categoricals

closes pandas-dev#16140

Author: jreback

pandas/tests/api/test_api.py

@@ -217,3 +217,17 @@ class TestTSLib(tm.TestCase):
     def test_deprecation_access_func(self):
         with catch_warnings(record=True):
             pd.tslib.Timestamp('20160101')
+
+
+class TestTypes(tm.TestCase):
+
+    def test_deprecation_access_func(self):
+        with tm.assert_produces_warning(
+                FutureWarning, check_stacklevel=False):
+            from pandas.types.concat import union_categoricals
+            c1 = pd.Categorical(list('aabc'))
+            c2 = pd.Categorical(list('abcd'))
+            union_categoricals(
+                [c1, c2],
+                sort_categories=True,
+                ignore_order=True)

pandas/types/__init__.py

@@ -0,0 +1,11 @@
+import warnings
+
+
+def union_categoricals(to_union, sort_categories=False, ignore_order=False):
+    warnings.warn("pandas.types.concat.union_categoricals is "
+                  "deprecated and will be removed in a future version.\n"
+                  "use pandas.api.types.union_categoricals",
+                  FutureWarning, stacklevel=2)
+    from pandas.api.types import union_categoricals
+    return union_categoricals(
+        to_union, sort_categories=sort_categories, ignore_order=ignore_order)