conftest.fail_on_pvlib_version applied to functions that require args or kwargs (#973)

* add *args to fail_on_pvlib_version

* working

* try this

* fix

* documentation

* review responses

* changes from review

* remove vestigial

* remove old comment

* inflate version number in test

* remove *args, **kwargs from fail_on_pvlib

* edits

* update whatsnew comment

Author: cwhanse

docs/sphinx/source/whatsnew/v0.8.0.rst

@@ -14,6 +14,8 @@ Bug fixes
 
 Testing
 ~~~~~~~
+* Decorator :py:func:`pvlib.conftest.fail_on_pvlib_version` can now be
+  applied to functions that require args or kwargs. (:pull:`973`)
 
 Documentation
 ~~~~~~~~~~~~~

pvlib/tests/conftest.py

@@ -6,6 +6,7 @@
 import pandas as pd
 from pkg_resources import parse_version
 import pytest
+from functools import wraps
 
 import pvlib
 
@@ -16,25 +17,24 @@
 # decorator takes one argument: the base version for which it should fail
 # for example @fail_on_pvlib_version('0.7') will cause a test to fail
 # on pvlib versions 0.7a, 0.7b, 0.7rc1, etc.
-# test function may not take args, kwargs, or fixtures.
 def fail_on_pvlib_version(version):
     # second level of decorator takes the function under consideration
     def wrapper(func):
         # third level defers computation until the test is called
         # this allows the specific test to fail at test runtime,
         # rather than at decoration time (when the module is imported)
-        def inner():
+        @wraps(func)
+        def inner(*args, **kwargs):
             # fail if the version is too high
             if pvlib_base_version >= parse_version(version):
                 pytest.fail('the tested function is scheduled to be '
                             'removed in %s' % version)
             # otherwise return the function to be executed
             else:
-                return func()
+                return func(*args, **kwargs)
         return inner
     return wrapper
 
-
 # commonly used directories in the tests
 TEST_DIR = Path(__file__).parent
 DATA_DIR = TEST_DIR.parent / 'data'

pvlib/tests/test_conftest.py

@@ -2,6 +2,7 @@
 
 from conftest import fail_on_pvlib_version
 
+from pvlib._deprecation import pvlibDeprecationWarning, deprecated
 
 @pytest.mark.xfail(strict=True,
                    reason='fail_on_pvlib_version should cause test to fail')
@@ -19,3 +20,26 @@ def test_fail_on_pvlib_version_pass():
 @fail_on_pvlib_version('100000.0')
 def test_fail_on_pvlib_version_fail_in_test():
     raise Exception
+
+
+# set up to test using fixtures with function decorated with
+# conftest.fail_on_pvlib_version
+@pytest.fixture()
+def some_data():
+    return "some data"
+
+
+def alt_func(*args):
+    return args
+
+
+deprec_func = deprecated('350.8', alternative='alt_func',
+                         name='deprec_func', removal='350.9')(alt_func)
+
+
+@fail_on_pvlib_version('350.9')
+def test_use_fixture_with_decorator(some_data):
+    # test that the correct data is returned by the some_data fixture
+    assert some_data == "some data"
+    with pytest.warns(pvlibDeprecationWarning):  # test for deprecation warning
+        deprec_func(some_data)