TST: add tests for config.py

correct a comment in the config code

pyfftw/config.py

@@ -27,7 +27,7 @@ def update(self, force=False):
         for name, value in os.environ.items():
             if name.startswith('PYFFTW_') or name == 'OMP_NUM_THREADS':
                 new_environ[name] = value
-        # We update the config variables if at least one NUMBA environment
+        # We update the config variables if at least one PYFFTW environment
         # variable was modified.  This lets the user modify values
         # directly in the config module without having them when
         # reload_config() is called by the compiler.

test/test_pyfftw_config.py

@@ -0,0 +1,97 @@
+
+from pyfftw import config, _threading_type
+
+
+from .test_pyfftw_base import run_test_suites
+
+import unittest
+import os
+from numpy.testing import assert_equal
+
+
+class ConfigTest(unittest.TestCase):
+
+    env_keys = ['PYFFTW_NUM_THREADS', 'OMP_NUM_THREADS',
+                'PYFFTW_PLANNER_EFFORT']
+    orig_env = {}
+
+    def setUp(self):
+        # store environment variables prior to testing
+        for key in self.env_keys:
+            self.orig_env[key] = os.environ.get(key, None)
+        return
+
+    def tearDown(self):
+        # resstore original environment variables values
+        for key in self.env_keys:
+            val = self.orig_env[key]
+            if val is None:
+                os.environ.pop(key, None)
+            else:
+                os.environ[key] = val
+        return
+
+    def test_default_config(self):
+        # unset environment variables if they were defined
+        os.environ.pop('PYFFTW_NUM_THREADS', None)
+        os.environ.pop('OMP_NUM_THREADS', None)
+        os.environ.pop('PYFFTW_PLANNER_EFFORT', None)
+        # defaults to single-threaded and FFTW_ESTIMATE
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 1)
+        assert_equal(config.PLANNER_EFFORT, 'FFTW_ESTIMATE')
+
+    @unittest.skipIf(_threading_type != 'OMP', reason='non-OpenMP build')
+    def test_default_threads_OpenMP(self):
+        # unset environment variables if they were defined
+        os.environ.pop('PYFFTW_NUM_THREADS', None)
+        os.environ.pop('OMP_NUM_THREADS', None)
+
+        # defaults to single-threaded if neither variable is defined
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 1)
+
+        # load default from OMP_NUM_THREADS environment variable
+        os.environ['OMP_NUM_THREADS'] = '2'
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 2)
+
+        # PYFFTW_NUM_THREADS overrides OMP_NUM_THREADS when both are defined
+        os.environ['PYFFTW_NUM_THREADS'] = '4'
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 4)
+
+    def test_non_default_config(self):
+        # set environment variables to non-default values
+        if _threading_type is None:
+            os.environ['PYFFTW_NUM_THREADS'] = '1'
+        else:
+            os.environ['PYFFTW_NUM_THREADS'] = '4'
+        os.environ['PYFFTW_PLANNER_EFFORT'] = 'FFTW_MEASURE'
+
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 4)
+        assert_equal(config.PLANNER_EFFORT, 'FFTW_MEASURE')
+
+        # set values to something else
+        config.NUM_THREADS = 6
+        config.PLANNER_EFFORT = 'FFTW_ESTIMATE'
+
+        # reload_config should preserve the user-defined values
+        config.reload_config()
+        assert_equal(config.NUM_THREADS, 6)
+        assert_equal(config.PLANNER_EFFORT, 'FFTW_ESTIMATE')
+
+        # can reset back to the values from the environment variables
+        config._env_reloader.reset()
+        assert_equal(config.NUM_THREADS, 4)
+        assert_equal(config.PLANNER_EFFORT, 'FFTW_MEASURE')
+
+
+test_cases = (ConfigTest, )
+
+test_set = None
+
+if __name__ == '__main__':
+
+    run_test_suites(test_cases, test_set)