Improve command package isolation.

pkg/commands/build/testdata/testcase-base-only/in/resources/networkpolicy.yaml

@@ -0,0 +1,13 @@
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: nginx
+spec:
+  podSelector:
+    matchExpressions:
+      - {key: app, operator: In, values: [test]}
+  ingress:
+    - from:
+        - podSelector:
+            matchLabels:
+              app: nginx