Merge pull request #3145 from getlantern/issue3143

add test for NonStopWriter

src/github.com/getlantern/flashlight/logging/logging.go

@@ -297,9 +297,8 @@ func NonStopWriter(writers ...io.Writer) io.Writer {
 // It never fails and always return the length of bytes passed in
 func (t *nonStopWriter) Write(p []byte) (int, error) {
 	for _, w := range t.writers {
-		if n, err := w.Write(p); err != nil {
-			return n, err
-		}
+		// intentionally not checking for errors
+		_, _ = w.Write(p)
 	}
 	return len(p), nil
 }

src/github.com/getlantern/flashlight/logging/logging_test.go

@@ -3,6 +3,7 @@ package logging
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"regexp"
 	"strings"
 	"testing"
@@ -12,6 +13,25 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+type BadWriter struct{}
+type GoodWriter struct{ counter int }
+
+func (w *BadWriter) Write(p []byte) (int, error) {
+	return 0, fmt.Errorf("Fail intentionally")
+}
+
+func (w *GoodWriter) Write(p []byte) (int, error) {
+	w.counter = len(p)
+	return w.counter, nil
+}
+
+func TestNonStopWriter(t *testing.T) {
+	b, g := BadWriter{}, GoodWriter{}
+	ns := NonStopWriter(&b, &g)
+	ns.Write([]byte("1234"))
+	assert.Equal(t, 4, g.counter, "Should write to all writers even when error encountered")
+}
+
 func TestLoggly(t *testing.T) {
 	var buf bytes.Buffer
 	var result map[string]interface{}