Add test for null value

kyaml/order/syncorder_test.go

@@ -183,6 +183,27 @@ pipeline:
     configPath: setters.yaml
   - image: set-namespace:v0.1
     configPath: ns.yaml
+`,
+		},
+		{
+			name: "sort fields with null value",
+			from: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  creationTimestamp: null
+  name: workspaces.app.terraform.io
+`,
+			to: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: workspaces.app.terraform.io
+  creationTimestamp: null
+`,
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  creationTimestamp: null
+  name: workspaces.app.terraform.io
 `,
 		},
 		{