Simplify and future-proof numba import in spa.py (pvlib#1944)

* remove numba version checking code

* set minimum numba in setup.py requirements

* remove same version check code in test_spa.py

* linter

* fix numba version check in `conftest.py`

* add `noqa: F401` to other import checks

* set minimum numba in pyproject.toml

Author: kandersolar

pvlib/spa.py

@@ -21,23 +21,15 @@ def nocompile(*args, **kwargs):
 
 if os.getenv('PVLIB_USE_NUMBA', '0') != '0':
     try:
-        from numba import jit, __version__
+        from numba import jit
     except ImportError:
         warnings.warn('Could not import numba, falling back to numpy ' +
                       'calculation')
         jcompile = nocompile
         USE_NUMBA = False
     else:
-        major, minor = __version__.split('.')[:2]
-        if int(major + minor) >= 17:
-            # need at least numba >= 0.17.0
-            jcompile = jit
-            USE_NUMBA = True
-        else:
-            warnings.warn('Numba version must be >= 0.17.0, falling back to ' +
-                          'numpy')
-            jcompile = nocompile
-            USE_NUMBA = False
+        jcompile = jit
+        USE_NUMBA = True
 else:
     jcompile = nocompile
     USE_NUMBA = False

pvlib/tests/conftest.py

@@ -119,7 +119,7 @@ def assert_frame_equal(left, right, **kwargs):
 
 
 try:
-    import ephem
+    import ephem  # noqa: F401
     has_ephem = True
 except ImportError:
     has_ephem = False
@@ -129,7 +129,7 @@ def assert_frame_equal(left, right, **kwargs):
 
 def has_spa_c():
     try:
-        from pvlib.spa_c_files.spa_py import spa_calc
+        from pvlib.spa_c_files.spa_py import spa_calc  # noqa: F401
     except ImportError:
         return False
     else:
@@ -139,20 +139,14 @@ def has_spa_c():
 requires_spa_c = pytest.mark.skipif(not has_spa_c(), reason="requires spa_c")
 
 
-def has_numba():
-    try:
-        import numba
-    except ImportError:
-        return False
-    else:
-        vers = numba.__version__.split('.')
-        if int(vers[0] + vers[1]) < 17:
-            return False
-        else:
-            return True
+try:
+    import numba   # noqa: F401
+    has_numba = True
+except ImportError:
+    has_numba = False
 
 
-requires_numba = pytest.mark.skipif(not has_numba(), reason="requires numba")
+requires_numba = pytest.mark.skipif(not has_numba, reason="requires numba")
 
 
 try:

pvlib/tests/test_spa.py

@@ -15,15 +15,7 @@
 import pandas as pd
 
 import unittest
-import pytest
-
-
-try:
-    from numba import __version__ as numba_version
-    numba_version_int = int(numba_version.split('.')[0] +
-                            numba_version.split('.')[1])
-except ImportError:
-    numba_version_int = 0
+from .conftest import requires_numba
 
 
 times = (pd.date_range('2003-10-17 12:30:30', periods=1, freq='D')
@@ -390,17 +382,15 @@ def test_julian_day(self):
         assert_almost_equal(JD, self.spa.julian_day(unixtimes)[0], 6)
 
 
-@pytest.mark.skipif(numba_version_int < 17,
-                    reason='Numba not installed or version not >= 0.17.0')
+@requires_numba
 class NumbaSpaTest(unittest.TestCase, SpaBase):
     """Import spa, compiling to numba, and run tests"""
     @classmethod
     def setUpClass(self):
         os.environ['PVLIB_USE_NUMBA'] = '1'
-        if numba_version_int >= 17:
-            import pvlib.spa as spa
-            spa = reload(spa)
-            self.spa = spa
+        import pvlib.spa as spa
+        spa = reload(spa)
+        self.spa = spa
 
     @classmethod
     def tearDownClass(self):

pyproject.toml

@@ -51,7 +51,7 @@ optional = [
     'cython',
     'ephem',
     'nrel-pysam',
-    'numba',
+    'numba >= 0.17.0',
     'solarfactors',
     'statsmodels',
 ]