Add unit test for pkg/jsonutils/streamwriter.go

Signed-off-by: Dao Cong Tien <tiendc@vn.fujitsu.com>

pkg/jsonutils/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
@@ -6,3 +6,10 @@ go_library(
     importpath = "k8s.io/kops/pkg/jsonutils",
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["streamwriter_test.go"],
+    embed = [":go_default_library"],
+    deps = ["//vendor/github.com/MakeNowJust/heredoc:go_default_library"],
+)

pkg/jsonutils/streamwriter_test.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+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 jsonutils
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/MakeNowJust/heredoc"
+)
+
+func TestWriteToken(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		indent   string
+		expected string
+	}{
+		{
+			name:   "WriteJson",
+			input:  heredoc.Doc(`{"key1": 123,"key2" : true   }  `),
+			indent: "",
+			expected: heredoc.Doc(`{
+			  "key1": 123,
+			  "key2": true
+			}`),
+		},
+		{
+			name:   "WriteJsonWithIndent",
+			input:  heredoc.Doc(`{"key1" :123, "999" : [123.5678,"abc"]  }`),
+			indent: "###",
+			expected: heredoc.Doc(`###{
+			###  "key1": 123,
+			###  "999": [
+			###    123.5678,
+			###    "abc"
+			###  ]
+			###}`),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			out := &JSONStreamWriter{
+				out:    &buf,
+				indent: test.indent,
+			}
+			in := json.NewDecoder(strings.NewReader(test.input))
+			for {
+				token, err := in.Token()
+				if err != nil {
+					if err == io.EOF { // No more token
+						break
+					} else {
+						t.Fatalf("unexpected error parsing json input: %v", err)
+					}
+				}
+				if err := out.WriteToken(token); err != nil {
+					t.Fatalf("error writing json: %v", err)
+				}
+			}
+			if buf.String() != test.expected {
+				t.Fatalf("Actual result:\n%s\nExpect:\n%s", buf.String(), test.expected)
+			}
+		})
+	}
+}