add test for issues raised in #2734

plugin/builtin/patchstrategicmergetransformer/PatchStrategicMergeTransformer_test.go

@@ -418,6 +418,162 @@ paths:
 	})
 }
 
+// issue #2734 -- https://github.com/kubernetes-sigs/kustomize/issues/2734
+// kyaml cleans up things some folks prefer it didnt
+// 1. []    -- see initContainers and imagePullSecrets
+// 2. {}    -- see emptyDir
+// 3. null  -- see creationTimestamp
+
+const anUncleanDeploymentResource = `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sas-crunchy-data-postgres-operator
+spec:
+  replicas: 1
+  template:
+    metadata:
+      creationTimestamp: null
+    spec:
+      serviceAccountName: postgres-operator
+      containers:
+      - name: apiserver
+        image: sas-crunchy-data-operator-api-server
+        imagePullPolicy: IfNotPresent
+        ports:
+        - containerPort: 8443
+        envFrom: []
+        volumeMounts:
+        - name: security-ssh
+          mountPath: /security-ssh
+        - mountPath: /tmp
+          name: tmp
+      imagePullSecrets: []
+      initContainers: []
+      volumes:
+      - emptyDir: {}
+        name: security-ssh
+      - emptyDir: {}
+        name: tmp
+`
+
+// This is the preffered result (and what we get with kustomize 3.7.0)
+const expectedCleanedDeployment = `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  labels:
+    workload.sas.com/class: stateless
+  name: sas-crunchy-data-postgres-operator
+spec:
+  replicas: 1
+  template:
+    metadata:
+      creationTimestamp: null
+      labels:
+        workload.sas.com/class: stateless
+    spec:
+      containers:
+      - envFrom: []
+        image: sas-crunchy-data-operator-api-server
+        imagePullPolicy: IfNotPresent
+        name: apiserver
+        ports:
+        - containerPort: 8443
+        volumeMounts:
+        - mountPath: /security-ssh
+          name: security-ssh
+        - mountPath: /tmp
+          name: tmp
+      imagePullSecrets: []
+      initContainers: []
+      serviceAccountName: postgres-operator
+      tolerations:
+      - effect: NoSchedule
+        key: workload.sas.com/class
+        operator: Equal
+        value: stateful
+      volumes:
+      - emptyDir: {}
+        name: security-ssh
+      - emptyDir: {}
+        name: tmp
+`
+
+// This is the current (incorrect) result we get with kustomize 3.8.1
+const currentCleanedDeployment = `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  labels:
+    workload.sas.com/class: stateless
+  name: sas-crunchy-data-postgres-operator
+spec:
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        workload.sas.com/class: stateless
+    spec:
+      containers:
+      - envFrom: []
+        image: sas-crunchy-data-operator-api-server
+        imagePullPolicy: IfNotPresent
+        name: apiserver
+        ports:
+        - containerPort: 8443
+        volumeMounts:
+        - mountPath: /security-ssh
+          name: security-ssh
+        - mountPath: /tmp
+          name: tmp
+      imagePullSecrets: []
+      initContainers: []
+      serviceAccountName: postgres-operator
+      tolerations:
+      - effect: NoSchedule
+        key: workload.sas.com/class
+        operator: Equal
+        value: stateful
+      volumes:
+      - name: security-ssh
+      - name: tmp
+`
+
+func TestPatchStrategicMergeTransformerCleanupItems(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarness(t).
+		PrepBuiltin("PatchStrategicMergeTransformer")
+	defer th.Reset()
+
+	th.WriteF("/patch.yaml", `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sas-crunchy-data-postgres-operator
+  labels:
+    workload.sas.com/class: stateless
+spec:
+  template:
+    metadata:
+      labels:
+        workload.sas.com/class: stateless
+    spec:
+      tolerations:
+        - effect: NoSchedule
+          key: workload.sas.com/class
+          operator: Equal
+          value: stateful
+`)
+
+	th.RunTransformerAndCheckResult(`
+apiVersion: builtin
+kind: PatchStrategicMergeTransformer
+metadata:
+  name: notImportantHere
+paths:
+- patch.yaml
+`,
+		anUncleanDeploymentResource,
+		currentCleanedDeployment) // prefer expectedCleanedDeployment
+}
+
 func TestStrategicMergeTransformerNoSchema(t *testing.T) {
 	th := kusttest_test.MakeEnhancedHarness(t).
 		PrepBuiltin("PatchStrategicMergeTransformer")
@@ -1314,4 +1470,3 @@ paths:
 
 	th.AssertActualEqualsExpected(rm, ``)
 }
-