Fix error message of CBackend for unsupported nodes

pystencils/backends/cbackend.py

@@ -169,7 +169,7 @@ class CBackend:
             method_name = "_print_" + cls.__name__
             if hasattr(self, method_name):
                 return getattr(self, method_name)(node)
-        raise NotImplementedError(self.__class__ + " does not support node of type " + str(type(node)))
+        raise NotImplementedError(self.__class__.__name__ + " does not support node of type " + node.__class__.__name__)
 
     def _print_KernelFunction(self, node):
         function_arguments = ["%s %s" % (str(s.symbol.dtype), s.symbol.name) for s in node.get_parameters()]

pystencils_tests/test_print_unsupported_node.py

+# -*- coding: utf-8 -*-
+#
+# Copyright © 2019 Stephan Seitz <stephan.seitz@fau.de>
+#
+# Distributed under terms of the GPLv3 license.
+
+"""
+
+"""
+import pytest
+
+import pystencils
+from pystencils.backends.cbackend import CBackend
+
+
+class UnsupportedNode(pystencils.astnodes.Node):
+
+    def __init__(self):
+        super().__init__()
+
+
+def test_print_unsupported_node():
+    with pytest.raises(NotImplementedError, match='CBackend does not support node of type UnsupportedNode'):
+        CBackend()(UnsupportedNode())
+
+
+def main():
+    test_print_unsupported_node()
+
+
+if __name__ == '__main__':
+    main()