diff --git a/metropolis/test/launch/launch.go b/metropolis/test/launch/launch.go
index 93e45a6..953025d 100644
--- a/metropolis/test/launch/launch.go
+++ b/metropolis/test/launch/launch.go
@@ -90,7 +90,7 @@
 func IdentityPortMap(ports []uint16) PortMap {
 	portMap := make(PortMap)
 	for _, port := range ports {
-		portMap[port] = uint16(port)
+		portMap[port] = port
 	}
 	return portMap
 }