Add a printer that knows how to print user-defined columns

pkg/kubectl/custom_column_printer_test.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	"bytes"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/api/v1"
+	"k8s.io/kubernetes/pkg/runtime"
+)
+
+func TestColumnPrint(t *testing.T) {
+	tests := []struct {
+		columns        []Column
+		obj            runtime.Object
+		expectedOutput string
+	}{
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+			},
+			obj: &v1.Pod{ObjectMeta: v1.ObjectMeta{Name: "foo"}},
+			expectedOutput: `NAME
+foo
+`,
+		},
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+			},
+			obj: &v1.PodList{
+				Items: []v1.Pod{
+					{ObjectMeta: v1.ObjectMeta{Name: "foo"}},
+					{ObjectMeta: v1.ObjectMeta{Name: "bar"}},
+				},
+			},
+			expectedOutput: `NAME
+foo
+bar
+`,
+		},
+		{
+			columns: []Column{
+				{
+					Header:    "NAME",
+					FieldSpec: "{.metadata.name}",
+				},
+				{
+					Header:    "API_VERSION",
+					FieldSpec: "{.apiVersion}",
+				},
+			},
+			obj: &v1.Pod{ObjectMeta: v1.ObjectMeta{Name: "foo"}, TypeMeta: v1.TypeMeta{APIVersion: "baz"}},
+			expectedOutput: `NAME      API_VERSION
+foo       baz
+`,
+		},
+	}
+
+	for _, test := range tests {
+		printer := &CustomColumnsPrinter{
+			Columns: test.columns,
+		}
+		buffer := &bytes.Buffer{}
+		if err := printer.PrintObj(test.obj, buffer); err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if buffer.String() != test.expectedOutput {
+			t.Errorf("\nexpected:\n'%s'\nsaw\n'%s'\n", test.expectedOutput, buffer.String())
+		}
+	}
+}