Improve detection of double-exposed functions + added a unittest

wsme/api.py

@@ -99,7 +99,7 @@ class FunctionDefinition(object):
         self.contenttype = None
 
         #: Dictionnary of protocol-specific options.
-        self.extra_options = {}
+        self.extra_options = None
 
     @classmethod
     def get(cls, func):
@@ -143,7 +143,7 @@ class expose(object):
 
     def __call__(self, func):
         func, fd = FunctionDefinition.get(func)
-        if fd.return_type is not None:
+        if fd.extra_options is not None:
             raise ValueError("This function is already exposed")
         fd.return_type = self.return_type
         fd.extra_options = self.options

wsme/tests/test_api.py

@@ -197,6 +197,17 @@ class TestController(unittest.TestCase):
         assert res.status_int == 400
         assert res.content_type == 'text/plain', res.content_type
 
+    def test_double_expose(self):
+        try:
+            class MyRoot(WSRoot):
+                @expose()
+                @expose()
+                def atest(self):
+                    pass
+            assert False, "A ValueError should have been raised"
+        except ValueError:
+            pass
+
     def test_getapi(self):
         class MyRoot(WSRoot):
             pass