Refactor the PrefixSuffixTransformer into separate prefix- and suffix transformers (#4318)

* Refactor prefix filter into its own filter, decoupled from the prefixsuffix filter

* Refactor prefix transformer into its own transformer, decoupled from the prefixsuffix transformer

* Refactor suffix filter into its own filter, decoupled from the prefixsuffix filter

* Refactor suffix transformer into its own transformer, decoupled from the prefixsuffix transformer

* Add a default nameSuffix field spec in addition to the namePrefix

* Remove the PrefixSuffixTransformer from the list of builtin transformers

* Add a multi-transformer to builtinhelpers.TransformFactories

* Remove the implementation of the prefixsuffixtransformer.PrefixSuffixTransformer

* Resolve style and format related feedback from the pull request

* Add test to test the legacy PrefixSuffixTransformer for BC purposes

plugin/builtin/prefixtransformer/PrefixTransformer_test.go

@@ -0,0 +1,166 @@
+// 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 TestPrefixTransformer(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarness(t).
+		PrepBuiltin("PrefixTransformer")
+	defer th.Reset()
+
+	rm := th.LoadAndRunTransformer(`
+apiVersion: builtin
+kind: PrefixTransformer
+metadata:
+  name: notImportantHere
+prefix: baked-
+fieldSpecs:
+  - path: metadata/name
+`, `
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: apple
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: apple
+spec:
+  ports:
+  - port: 7002
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  name: crd
+---
+apiVersion: apiregistration.k8s.io/v1
+kind: APIService
+metadata:
+  name: apiservice
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+`)
+
+	th.AssertActualEqualsExpected(rm, `
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: apple
+---
+apiVersion: v1
+kind: Service
+metadata:
+  annotations:
+    internal.config.kubernetes.io/prefixes: baked-
+    internal.config.kubernetes.io/previousKinds: Service
+    internal.config.kubernetes.io/previousNames: apple
+    internal.config.kubernetes.io/previousNamespaces: default
+  name: baked-apple
+spec:
+  ports:
+  - port: 7002
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  name: crd
+---
+apiVersion: apiregistration.k8s.io/v1
+kind: APIService
+metadata:
+  name: apiservice
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  annotations:
+    internal.config.kubernetes.io/prefixes: baked-
+    internal.config.kubernetes.io/previousKinds: ConfigMap
+    internal.config.kubernetes.io/previousNames: cm
+    internal.config.kubernetes.io/previousNamespaces: default
+  name: baked-cm
+`)
+
+	rm = th.LoadAndRunTransformer(`
+apiVersion: builtin
+kind: PrefixTransformer
+metadata:
+  name: notImportantHere
+prefix: test-
+fieldSpecs:
+  - kind: Deployment
+    path: metadata/name
+  - kind: Deployment
+    path: spec/template/spec/containers/name
+`, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deployment
+spec:
+  template:
+    spec:
+      containers:
+      - image: myapp
+        name: main
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  name: crd
+---
+apiVersion: apiregistration.k8s.io/v1
+kind: APIService
+metadata:
+  name: apiservice
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+`)
+
+	th.AssertActualEqualsExpected(rm, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  annotations:
+    internal.config.kubernetes.io/prefixes: test-
+    internal.config.kubernetes.io/previousKinds: Deployment
+    internal.config.kubernetes.io/previousNames: deployment
+    internal.config.kubernetes.io/previousNamespaces: default
+  name: test-deployment
+spec:
+  template:
+    spec:
+      containers:
+      - image: myapp
+        name: test-main
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  name: crd
+---
+apiVersion: apiregistration.k8s.io/v1
+kind: APIService
+metadata:
+  name: apiservice
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+`)
+}