Move the extensions resource to common/.
diff --git a/openstack/common/extensions/urls_test.go b/openstack/common/extensions/urls_test.go
new file mode 100644
index 0000000..2a1e6a1
--- /dev/null
+++ b/openstack/common/extensions/urls_test.go
@@ -0,0 +1,26 @@
+package extensions
+
+import (
+	"testing"
+
+	"github.com/rackspace/gophercloud"
+	th "github.com/rackspace/gophercloud/testhelper"
+)
+
+const endpoint = "http://localhost:57909/"
+
+func endpointClient() *gophercloud.ServiceClient {
+	return &gophercloud.ServiceClient{Endpoint: endpoint}
+}
+
+func TestExtensionURL(t *testing.T) {
+	actual := extensionURL(endpointClient(), "agent")
+	expected := endpoint + "v2.0/extensions/agent"
+	th.AssertEquals(t, expected, actual)
+}
+
+func TestListExtensionURL(t *testing.T) {
+	actual := listExtensionURL(endpointClient())
+	expected := endpoint + "v2.0/extensions"
+	th.AssertEquals(t, expected, actual)
+}