Rackspace Auto Scale: Add policies Update()
diff --git a/rackspace/autoscale/v1/policies/fixtures.go b/rackspace/autoscale/v1/policies/fixtures.go
index 587c5e7..a66d6d1 100644
--- a/rackspace/autoscale/v1/policies/fixtures.go
+++ b/rackspace/autoscale/v1/policies/fixtures.go
@@ -117,6 +117,16 @@
 }
 `
 
+// PolicyUpdateRequest contains the canned body of a policies.Update request.
+const PolicyUpdateRequest = `
+{
+  "name": "updated webhook policy",
+  "type": "webhook",
+  "cooldown": 600,
+  "changePercent": 6.6
+}
+`
+
 var (
 	// WebhookPolicy is a Policy corresponding to the first result in PolicyListBody.
 	WebhookPolicy = Policy{
@@ -199,3 +209,20 @@
 		fmt.Fprintf(w, PolicyGetBody)
 	})
 }
+
+// HandlePolicyUpdateSuccessfully sets up the test server to respond to a policies Update request.
+func HandlePolicyUpdateSuccessfully(t *testing.T) {
+	groupID := "60b15dad-5ea1-43fa-9a12-a1d737b4da07"
+	policyID := "2b48d247-0282-4b9d-8775-5c4b67e8e649"
+
+	path := fmt.Sprintf("/groups/%s/policies/%s", groupID, policyID)
+
+	th.Mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
+		th.TestMethod(t, r, "PUT")
+		th.TestHeader(t, r, "X-Auth-Token", client.TokenID)
+
+		th.TestJSONRequest(t, r, PolicyUpdateRequest)
+
+		w.WriteHeader(http.StatusNoContent)
+	})
+}