Adds PrependGroupingObject() as apply pre-processor

cmd/kubectl/kubectlcobra/commands_test.go

@@ -0,0 +1,58 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// package kubectlcobra contains cobra commands from kubectl
+package kubectlcobra
+
+import (
+	"testing"
+
+	"k8s.io/cli-runtime/pkg/resource"
+	"k8s.io/kubectl/pkg/cmd/apply"
+)
+
+func TestPrependGroupingObject(t *testing.T) {
+	tests := []struct {
+		infos []*resource.Info
+	}{
+		{
+			infos: []*resource.Info{copyGroupingInfo()},
+		},
+		{
+			infos: []*resource.Info{pod1Info, pod3Info, copyGroupingInfo()},
+		},
+		{
+			infos: []*resource.Info{pod1Info, pod2Info, copyGroupingInfo(), pod3Info},
+		},
+	}
+
+	for _, test := range tests {
+		applyOptions := createApplyOptions(test.infos)
+		f := PrependGroupingObject(applyOptions)
+		err := f()
+		if err != nil {
+			t.Errorf("Error running pre-processor callback: %s", err)
+		}
+		infos, _ := applyOptions.GetObjects()
+		if len(test.infos) != len(infos) {
+			t.Fatalf("Wrong number of objects after prepending grouping object")
+		}
+		groupingInfo := infos[0]
+		if !isGroupingObject(groupingInfo.Object) {
+			t.Fatalf("First object is not the grouping object")
+		}
+		inventory, _ := retrieveInventoryFromGroupingObj(infos)
+		if len(inventory) != (len(infos) - 1) {
+			t.Errorf("Wrong number of inventory items stored in grouping object")
+		}
+	}
+
+}
+
+// createApplyOptions is a helper function to assemble the ApplyOptions
+// with the passed objects (infos).
+func createApplyOptions(infos []*resource.Info) *apply.ApplyOptions {
+	applyOptions := &apply.ApplyOptions{}
+	applyOptions.SetObjects(infos)
+	return applyOptions
+}