Add negative test for  set server metadata

* Raise exception while item in uri is different then
* one passed in body during set server metadata for a key

Fixes LP bug #1114979

Change-Id: I47094ed588b0351d2a4a83fbc1fd09d6e132f487
diff --git a/tempest/tests/compute/servers/test_server_metadata.py b/tempest/tests/compute/servers/test_server_metadata.py
index ef1b956..ce7a6a8 100644
--- a/tempest/tests/compute/servers/test_server_metadata.py
+++ b/tempest/tests/compute/servers/test_server_metadata.py
@@ -162,6 +162,21 @@
                       'not succeed')
 
     @attr(type='negative')
+    def test_set_server_metadata_item_incorrect_uri_key(self):
+        #Raise BadRequest if key in uri does not match
+        #the key passed in body.
+
+        meta = {'testkey': 'testvalue'}
+        try:
+            resp, metadata = self.client.set_server_metadata_item(
+                                        self.server_id, 'key', meta)
+        except exceptions.BadRequest:
+            pass
+        else:
+            self.fail('Should raise BadRequest if URI key does not match key'
+                      'passed in the body')
+
+    @attr(type='negative')
     def test_set_nonexistant_server_metadata(self):
         # Negative test: Set metadata on a non existant server should not
         # succeed