GH1055 Add pandas.api.typing to pandas-stubs

pandas-stubs/api/typing/__init__.pyi

@@ -0,0 +1,29 @@
+from pandas.core.groupby import (
+    DataFrameGroupBy as DataFrameGroupBy,
+    SeriesGroupBy as SeriesGroupBy,
+)
+from pandas.core.resample import (
+    DatetimeIndexResamplerGroupby as DatetimeIndexResamplerGroupby,
+    PeriodIndexResamplerGroupby as PeriodIndexResamplerGroupby,
+    Resampler as Resampler,
+    TimedeltaIndexResamplerGroupby as TimedeltaIndexResamplerGroupby,
+    TimeGrouper as TimeGrouper,
+)
+from pandas.core.window import (
+    Expanding as Expanding,
+    ExpandingGroupby as ExpandingGroupby,
+    ExponentialMovingWindow as ExponentialMovingWindow,
+    ExponentialMovingWindowGroupby as ExponentialMovingWindowGroupby,
+    Rolling as Rolling,
+    RollingGroupby as RollingGroupby,
+    Window as Window,
+)
+
+from pandas._libs import NaTType as NaTType
+from pandas._libs.missing import NAType as NAType
+
+from pandas.io.json._json import JsonReader as JsonReader
+
+# SASReader is not defined so commenting it out for now
+# from pandas.io.sas.sasreader import SASReader as SASReader
+from pandas.io.stata import StataReader as StataReader

tests/test_api_typing.py

@@ -0,0 +1,47 @@
+"""Test module for classes in pandas.api.typing."""
+
+import numpy as np
+import pandas as pd
+from pandas.api.typing import (
+    DataFrameGroupBy,
+    DatetimeIndexResamplerGroupby,
+    NAType,
+    SeriesGroupBy,
+)
+from typing_extensions import assert_type
+
+from tests import check
+
+
+def test_dataframegroupby():
+    df = pd.DataFrame({"a": [1, 2, 3]})
+    check(
+        assert_type(df.groupby("a"), DataFrameGroupBy),
+        DataFrameGroupBy,
+    )
+
+
+def test_seriesgroupby():
+    sr: pd.Series[int] = pd.Series([1, 2, 3], index=pd.Index(["a", "b", "a"]))
+    check(
+        assert_type(sr.groupby(level=0), SeriesGroupBy),
+        SeriesGroupBy,
+    )
+
+
+def tests_datetimeindexersamplergroupby() -> None:
+    idx = pd.date_range("1999-1-1", periods=365, freq="D")
+    df = pd.DataFrame(
+        np.random.standard_normal((365, 2)), index=idx, columns=["col1", "col2"]
+    )
+    gb_df = df.groupby("col2")
+    check(
+        assert_type(gb_df.resample("ME"), DatetimeIndexResamplerGroupby),
+        DatetimeIndexResamplerGroupby,
+        pd.DataFrame,
+    )
+
+
+def test_natype() -> None:
+    i64dt = pd.Int64Dtype()
+    check(assert_type(i64dt.na_value, NAType), NAType)