Add calvin duplicator example plugin.

plugin/someteam.example.com/v1/calvinduplicator/CalvinDuplicator_test.go

@@ -0,0 +1,57 @@
+// Copyright 2021 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package main_test
+
+import (
+	"testing"
+
+	kusttest_test "sigs.k8s.io/kustomize/api/testutils/kusttest"
+)
+
+func TestCalvinDuplicatorPlugin(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarness(t).
+		BuildGoPlugin("someteam.example.com", "v1", "CalvinDuplicator")
+	defer th.Reset()
+
+	m := th.LoadAndRunTransformer(`
+apiVersion: someteam.example.com/v1
+kind: CalvinDuplicator
+metadata:
+  name: whatever
+count: 3
+name: calvin
+`,
+		`apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: calvin
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fred
+`)
+
+	th.AssertActualEqualsExpectedNoIdAnnotations(m, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: calvin-1
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: calvin-2
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: calvin-3
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fred
+`)
+}