add helpful error message for failed julia dependency imports

rmgpy/rmg/reactors.py

@@ -35,7 +35,7 @@
 import sys
 import logging
 import itertools
-
+import warnings
 if __debug__:
     try:
         from os.path import dirname, abspath, join, exists
@@ -46,14 +46,17 @@
         from diffeqpy import de
         from julia import Main 
     except:
-        pass
+        raise RuntimeError("Unable to load system Julia image during debug run.")
 else:
     try:
         from pyrms import rms
         from diffeqpy import de
         from julia import Main
     except:
-        pass
+        if 'nose' not in sys.modules.keys():
+            raise RuntimeError("Import of Julia dependencies failed. Ensure the environment is correctly built and Julia dependencies have been linked properly.")
+        else:
+            warnings.warn("Failed Julia imports ignored, assuming execution in nosetests", RuntimeWarning)
 
 from rmgpy.species import Species
 from rmgpy.reaction import Reaction

rmgpy/rmg/reactorsTest.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+
+###############################################################################
+#                                                                             #
+# RMG - Reaction Mechanism Generator                                          #
+#                                                                             #
+# Copyright (c) 2002-2021 Prof. William H. Green (whgreen@mit.edu),           #
+# Prof. Richard H. West (r.west@neu.edu) and the RMG Team (rmg_dev@mit.edu)   #
+#                                                                             #
+# Permission is hereby granted, free of charge, to any person obtaining a     #
+# copy of this software and associated documentation files (the 'Software'),  #
+# to deal in the Software without restriction, including without limitation   #
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,    #
+# and/or sell copies of the Software, and to permit persons to whom the       #
+# Software is furnished to do so, subject to the following conditions:        #
+#                                                                             #
+# The above copyright notice and this permission notice shall be included in  #
+# all copies or substantial portions of the Software.                         #
+#                                                                             #
+# THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  #
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    #
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE #
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER      #
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING     #
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER         #
+# DEALINGS IN THE SOFTWARE.                                                   #
+#                                                                             #
+###############################################################################
+
+import unittest
+import sys
+
+from unittest.mock import MagicMock, patch
+
+###################################################
+
+
+class TestReactors(unittest.TestCase):
+
+    def test_missing_julia_warning(self):
+        """
+        Ensure that a missing Julia install will raise an error to the user.
+        """
+        # make a MagicMock that replaces pyrms and makes it look like it is missing
+        rmsModuleMock = MagicMock()
+        rmsModuleMock.side_effect = ModuleNotFoundError
+        with patch.dict('sys.modules', pyrms=rmsModuleMock):
+            # RuntimeError is not raised when running test - trick it into thinking we are not in a test
+            del sys.modules['nose']
+            # use a second context to check for the error on import
+            with self.assertRaises(RuntimeError):
+                import rmgpy.rmg.reactors
+
+
+if __name__ == '__main__':
+    unittest.main()