BUG: constrain cftime to >=1.1.1 (#947)

* limit cftime to <=1.1.0 for all but Python3.5

* add what's new

* Revert "limit cftime to <=1.1.0 for all but Python3.5"

This reverts commit 1afd3cb.

* add only_use_python_datetimes, switch off only_use_cftime_datetimes

* limit cftime>=1.1.1

* update what's new

* install cftime from pip instead

* selectively fail tests

* raise Exception for old cftime

* Revert "install cftime from pip instead"

This reverts commit 251b221.

* limit cftime, skip<python3.6

* fix lint, import sys

* set cftime<=1.1.0

* fix test_forecast

* add new cftime kwargs, xfail for cftime>1.1.0

* pin to 1.1.1 and above

* improve what's new

* remove unnecessary conda pinning

* remove sys

* test not limiting cftime

* Revert "test not limiting cftime"

This reverts commit f210b11.

Author: CameronTStark

docs/sphinx/source/whatsnew/v0.7.2.rst

@@ -91,6 +91,9 @@ Documentation
 Requirements
 ~~~~~~~~~~~~
 * nrel-pysam (optional) minimum set to v1.0.0 (:issue:`874`)
+* cftime (optional) minimum set to >=1.1.1. Use of
+  `only_use_python_datetimes` kwarg in `netCDF4.num2date` in forecast.py
+  requires >=1.1.1 which is >=Python3.6. (:pull:`947`)
 
 Contributors
 ~~~~~~~~~~~~
@@ -103,3 +106,4 @@ Contributors
 * Siyan (Veronica) Guo (:ghuser:`veronicaguo`)
 * Eric Fitch (:ghuser:`ericf900`)
 * Joseph Palakapilly (:ghuser:`JPalakapilly`)
+* Auguste Colle(:ghuser:`augustecolle`)

pvlib/forecast.py

@@ -406,7 +406,8 @@ def set_time(self, time):
         pandas.DatetimeIndex
         '''
         times = num2date(time[:].squeeze(), time.units,
-                         only_use_cftime_datetimes=False)
+                         only_use_cftime_datetimes=False,
+                         only_use_python_datetimes=True)
         self.time = pd.DatetimeIndex(pd.Series(times), tz=self.location.tz)
 
     def cloud_cover_to_ghi_linear(self, cloud_cover, ghi_clear, offset=35,

pvlib/tests/conftest.py

@@ -156,6 +156,20 @@ def has_numba():
 requires_pysam = pytest.mark.skipif(not has_pysam, reason="requires PySAM")
 
 
+try:
+    import cftime  # noqa: F401
+
+    has_recent_cftime = parse_version(cftime.__version__) > parse_version(
+        "1.1.0"
+    )
+except ImportError:
+    has_recent_cftime = False
+
+requires_recent_cftime = pytest.mark.skipif(
+    not has_recent_cftime, reason="requires cftime > 1.1.0"
+)
+
+
 @pytest.fixture(scope="session")
 def sam_data():
     data = {}

pvlib/tests/test_forecast.py

@@ -6,7 +6,12 @@
 import pytest
 from numpy.testing import assert_allclose
 
-from conftest import requires_siphon, has_siphon, skip_windows
+from conftest import (
+    requires_siphon,
+    has_siphon,
+    skip_windows,
+    requires_recent_cftime,
+)
 from conftest import RERUNS, RERUNS_DELAY
 
 pytestmark = pytest.mark.skipif(not has_siphon, reason='requires siphon')
@@ -60,6 +65,7 @@ def model(request):
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_process_data(model):
@@ -78,6 +84,7 @@ def test_process_data(model):
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_bad_kwarg_get_data():
@@ -90,6 +97,7 @@ def test_bad_kwarg_get_data():
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_bad_kwarg_get_processed_data():
@@ -102,6 +110,7 @@ def test_bad_kwarg_get_processed_data():
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_how_kwarg_get_processed_data():
@@ -112,6 +121,7 @@ def test_how_kwarg_get_processed_data():
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_vert_level():
@@ -122,6 +132,7 @@ def test_vert_level():
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_datetime():
@@ -132,6 +143,7 @@ def test_datetime():
 
 
 @requires_siphon
+@requires_recent_cftime
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
 def test_queryvariables():

setup.py

@@ -45,7 +45,7 @@
                  'pytest-timeout', 'pytest-rerunfailures', 'pytest-remotedata']
 EXTRAS_REQUIRE = {
     'optional': ['ephem', 'cython', 'netcdf4', 'nrel-pysam', 'numba',
-                 'pvfactors', 'scipy', 'siphon', 'tables'],
+                 'pvfactors', 'scipy', 'siphon', 'tables', 'cftime >= 1.1.1'],
     'doc': ['ipython', 'matplotlib', 'sphinx == 1.8.5', 'sphinx_rtd_theme',
             'sphinx-gallery', 'docutils == 0.15.2'],
     'test': TESTS_REQUIRE