[common] add a test for WriteFileAtomic

common/os_test.go

@@ -0,0 +1,29 @@
+package common
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestWriteFileAtomic(t *testing.T) {
+	data := []byte("Becatron")
+	fname := fmt.Sprintf("/tmp/write-file-atomic-test-%v.txt", time.Now().UnixNano())
+	err := WriteFileAtomic(fname, data, 0664)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rData, err := ioutil.ReadFile(fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(data, rData) {
+		t.Fatalf("data mismatch: %v != %v", data, rData)
+	}
+	if err := os.Remove(fname); err != nil {
+		t.Fatal(err)
+	}
+}