Add a unit test for MakePipelineOptionsFileAndEnvVar (#31732)

* Add unit test for MakePipelineOptionsFileAndEnvVar

* Add coverage for validating options string is JSON

sdks/go/container/tools/pipeline_options.go

@@ -16,6 +16,7 @@
 package tools
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 )
@@ -31,6 +32,10 @@ func MakePipelineOptionsFileAndEnvVar(options string) error {
 		return fmt.Errorf("unable to create %v: %w", fn, err)
 	}
 	defer f.Close()
+	var js map[string]interface{}
+	if json.Unmarshal([]byte(options), &js) != nil {
+		return fmt.Errorf("options string is not JSON formatted %v", options)
+	}
 	if _, err := f.WriteString(options); err != nil {
 		return fmt.Errorf("error writing %v: %w", f.Name(), err)
 	}

sdks/go/container/tools/pipeline_options_test.go

@@ -0,0 +1,58 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You 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 tools
+
+import (
+	"os"
+	"testing"
+)
+
+func TestMakePipelineOptionsFileAndEnvVar(t *testing.T) {
+	tests := []struct {
+		name          string
+		inputOptions  string
+		expectedError string
+	}{
+		{
+			"empty options",
+			"{}",
+			"",
+		},
+		{
+			"valid options",
+			"{\"abc\": 123}",
+			"",
+		},
+		{
+			"invalid options",
+			"{4}",
+			"options string is not JSON formatted {4}",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Cleanup(os.Clearenv)
+			err := MakePipelineOptionsFileAndEnvVar(test.inputOptions)
+			if err != nil {
+				if got, want := err.Error(), test.expectedError; got != want {
+					t.Errorf("got error: %v, want error: %v", got, want)
+				}
+			}
+		})
+	}
+	os.Remove("pipeline_options.json")
+}