CI: Start Testing on Python 3.11

.github/workflows/python-dev.yml

@@ -29,7 +29,7 @@ env:
 
 jobs:
   build:
-    if: false # Comment this line out to "unfreeze"
+    #if: false # Comment this line out to "unfreeze"
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
@@ -55,13 +55,14 @@ jobs:
         python-version: '3.11-dev'
 
     - name: Install dependencies
-      shell: bash -el {0}
+      #shell: bash -el {0}
       run: |
-        python3 -m pip install --upgrade pip setuptools wheel
-        python3 -m pip install -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
-        python3 -m pip install git+https://github.com/nedbat/coveragepy.git
-        python3 -m pip install cython python-dateutil pytz hypothesis pytest>=6.2.5 pytest-xdist pytest-cov pytest-asyncio>=0.17
-        python3 -m pip list
+        python -m pip install --upgrade pip setuptools wheel
+        # pip install -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
+        python -m pip install git+https://github.com/nedbat/coveragepy.git
+        python -m pip install git+https://github.com/numpy/numpy.git
+        python -m pip install cython python-dateutil pytz hypothesis pytest>=6.2.5 pytest-xdist pytest-cov pytest-asyncio
+        python -m pip list
 
     - name: Build Pandas
       run: |

pandas/compat/__init__.py

@@ -28,6 +28,7 @@
 
 PY39 = sys.version_info >= (3, 9)
 PY310 = sys.version_info >= (3, 10)
+PY311 = sys.version_info >= (3, 11)
 PYPY = platform.python_implementation() == "PyPy"
 IS64 = sys.maxsize > 2**32
 

pandas/conftest.py

@@ -79,6 +79,14 @@
     # Import "zoneinfo" could not be resolved (reportMissingImports)
     import zoneinfo  # type: ignore[no-redef]
 
+    # Although zoneinfo can be imported in Py39, it is effectively
+    # "not available" without tzdata/IANA tz data.
+    # We will set zoneinfo to not found in this case
+    try:
+        utc_zoneinfo = zoneinfo.ZoneInfo("UTC")
+    except zoneinfo.ZoneInfoNotFoundError:
+        zoneinfo = None
+
 # Until https://github.com/numpy/numpy/issues/19078 is sorted out, just suppress
 suppress_npdev_promotion_warning = pytest.mark.filterwarnings(
     "ignore:Promotion of numbers and bools:FutureWarning"

pandas/tests/io/parser/common/test_read_errors.py

@@ -12,6 +12,7 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PY311
 from pandas.errors import (
     EmptyDataError,
     ParserError,
@@ -230,7 +231,7 @@ def test_null_byte_char(all_parsers):
     names = ["a", "b"]
     parser = all_parsers
 
-    if parser.engine == "c":
+    if parser.engine == "c" or PY311:
         expected = DataFrame([[np.nan, "foo"]], columns=names)
         out = parser.read_csv(StringIO(data), names=names)
         tm.assert_frame_equal(out, expected)

pandas/tests/io/parser/test_quoting.py

@@ -80,7 +80,10 @@ def test_null_quote_char(all_parsers, quoting, quote_char):
 
     if quoting != csv.QUOTE_NONE:
         # Sanity checking.
-        msg = "quotechar must be set if quoting enabled"
+        msg = (
+            r"(quotechar must be set if quoting enabled|"
+            r'"quotechar" must be a 1-character string)'
+        )
 
         with pytest.raises(TypeError, match=msg):
             parser.read_csv(StringIO(data), **kwargs)

pandas/tests/scalar/test_nat.py

@@ -220,16 +220,14 @@ def test_missing_public_nat_methods(klass, expected):
     assert missing == expected
 
 
-def _get_overlap_public_nat_methods(klass, as_tuple=False):
+def _get_overlap_public_nat_methods(klass):
     """
     Get overlapping public methods between NaT and another class.
 
     Parameters
     ----------
     klass : type
         The class to compare with NaT
-    as_tuple : bool, default False
-        Whether to return a list of tuples of the form (klass, method).
 
     Returns
     -------
@@ -249,9 +247,6 @@ def _get_overlap_public_nat_methods(klass, as_tuple=False):
         ts_names = dir(Timestamp)
         overlap = [x for x in overlap if x not in ts_names]
 
-    if as_tuple:
-        overlap = [(klass, method) for method in overlap]
-
     overlap.sort()
     return overlap
 
@@ -315,30 +310,28 @@ def test_overlap_public_nat_methods(klass, expected):
 
 
 @pytest.mark.parametrize(
-    "compare",
-    (
-        _get_overlap_public_nat_methods(Timestamp, True)
-        + _get_overlap_public_nat_methods(Timedelta, True)
-    ),
+    "klass",
+    (Timestamp, Timedelta),
 )
-def test_nat_doc_strings(compare):
+def test_nat_doc_strings(klass):
     # see gh-17327
     #
     # The docstrings for overlapping methods should match.
-    klass, method = compare
-    klass_doc = getattr(klass, method).__doc__
+    methods = _get_overlap_public_nat_methods(klass)
+    for method in methods:
+        klass_doc = getattr(klass, method).__doc__
 
-    # Ignore differences with Timestamp.isoformat() as they're intentional
-    if klass == Timestamp and method == "isoformat":
-        return
+        # Ignore differences with Timestamp.isoformat() as they're intentional
+        if klass == Timestamp and method == "isoformat":
+            return
 
-    if method == "to_numpy":
-        # GH#44460 can return either dt64 or td64 depending on dtype,
-        #  different docstring is intentional
-        return
+        if method == "to_numpy":
+            # GH#44460 can return either dt64 or td64 depending on dtype,
+            #  different docstring is intentional
+            return
 
-    nat_doc = getattr(NaT, method).__doc__
-    assert klass_doc == nat_doc
+        nat_doc = getattr(NaT, method).__doc__
+        assert klass_doc == nat_doc
 
 
 _ops = {