Now prints a nice warning instead of failing tests when js2py isn't installed

tests/__main__.py

@@ -10,7 +10,7 @@ from .test_reconstructor import TestReconstructor
 try:
     from .test_nearley.test_nearley import TestNearley
 except ImportError:
-    pass
+    logging.warn("Warning: Skipping tests for Nearley (js2py required)")
 
 # from .test_selectors import TestSelectors
 # from .test_grammars import TestPythonG, TestConfigG

tests/test_nearley/test_nearley.py

@@ -15,9 +15,12 @@ NEARLEY_PATH = os.path.join(TEST_PATH, 'nearley')
 BUILTIN_PATH = os.path.join(NEARLEY_PATH, 'builtin')
 
 if not os.path.exists(NEARLEY_PATH):
-    print("Skipping Nearley tests!")
+    logging.warn("Nearley not installed. Skipping Nearley tests!")
     raise ImportError("Skipping Nearley tests!")
 
+import js2py    # Ensures that js2py exists, to avoid failing tests
+
+
 class TestNearley(unittest.TestCase):
     def test_css(self):
         fn = os.path.join(NEARLEY_PATH, 'examples/csscolor.ne')