diff --git a/include/mapnik/value.hpp b/include/mapnik/value.hpp
index 68726958b..dba068f6a 100644
--- a/include/mapnik/value.hpp
+++ b/include/mapnik/value.hpp
@@ -1010,6 +1010,13 @@ struct is_null : public boost::static_visitor<bool>
         boost::ignore_unused_variable_warning(val);
         return false;
     }
+
+    template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
+    bool operator() (boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& val)
+        const
+    {
+        return boost::apply_visitor(*this, val);
+    }
 };
 
 } // namespace impl
diff --git a/tests/run_tests.py b/tests/run_tests.py
index 45326b0ef..4538571b1 100755
--- a/tests/run_tests.py
+++ b/tests/run_tests.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 
 import sys
 
@@ -9,12 +8,7 @@ except ImportError, e:
     sys.stderr.write("Unable to run python tests: the third party 'nose' module is required\nTo install 'nose' do:\n\tsudo pip install nose (or on debian systems: apt-get install python-nose): %s\n" % e)
     sys.exit(1)
 
-try:
-    import mapnik
-except ImportError:
-    print '\x1b[31m✘\x1b[0m (\x1b[34m%s\x1b[0m)' % 'import mapnik failed - tests require python bindings'
-    sys.exit(0)
-    
+import mapnik    
 from python_tests.utilities import TodoPlugin
 from nose.plugins.doctests import Doctest
 
diff --git a/tests/visual_tests/test.py b/tests/visual_tests/test.py
index 379c2971e..1a34b3c44 100755
--- a/tests/visual_tests/test.py
+++ b/tests/visual_tests/test.py
@@ -2,16 +2,11 @@
 # -*- coding: utf-8 -*-
 
 import sys
-
-try:
-    import mapnik
-    mapnik.logger.set_severity(mapnik.severity_type.None)
-    #mapnik.logger.set_severity(mapnik.severity_type.Debug)
-except ImportError:
-    print '\x1b[31m✘\x1b[0m (\x1b[34m%s\x1b[0m)' % 'import mapnik failed - tests require python bindings'
-    sys.exit(0)
-
+import mapnik
+mapnik.logger.set_severity(mapnik.severity_type.None)
+#mapnik.logger.set_severity(mapnik.severity_type.Debug)
 import shutil
+import sys
 import os.path
 from compare import compare, compare_grids