Fixed permissions test

1 files changed, 17 insertions, 1 deletions

diff --git a/test/pkg_test4/__init__.py b/test/pkg_test4/__init__.py
index 0e19558..ba9ddac 100644
--- a/test/pkg_test4/__init__.py
+++ b/test/pkg_test4/__init__.py
@@ -1,9 +1,25 @@
 # Tests proper handling of lextab and parsetab files in package structures
+# Check of warning messages when files aren't writable
 
 # Here for testing purposes
 import sys
 if '..' not in sys.path:  
     sys.path.insert(0, '..')
 
-from .parsing.calcparse import parser
+import ply.lex
+import ply.yacc
+
+def patched_open(filename, mode):
+    if 'w' in mode:
+        raise IOError("Permission denied %r" % filename)
+    return open(filename, mode)
+
+ply.lex.open = patched_open
+ply.yacc.open = patched_open
+try:
+    from .parsing.calcparse import parser
+finally:
+    del ply.lex.open
+    del ply.yacc.open
+