[chore] refactor a struct used in testing to unexport it (#40229)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: atoulme

exporter/fileexporter/buffered_writer_test.go

@@ -24,18 +24,18 @@ const (
 	SizeMegaByte
 )
 
-type NopWriteCloser struct {
+type nopWriteCloser struct {
 	w io.Writer
 }
 
-func (NopWriteCloser) Close() error                    { return nil }
-func (wc *NopWriteCloser) Write(p []byte) (int, error) { return wc.w.Write(p) }
+func (nopWriteCloser) Close() error                    { return nil }
+func (wc *nopWriteCloser) Write(p []byte) (int, error) { return wc.w.Write(p) }
 
 func TestBufferedWrites(t *testing.T) {
 	t.Parallel()
 
 	b := bytes.NewBuffer(nil)
-	w := newBufferedWriteCloser(&NopWriteCloser{b})
+	w := newBufferedWriteCloser(&nopWriteCloser{b})
 
 	_, err := w.Write([]byte(msg))
 	require.NoError(t, err, "Must not error when writing data")
@@ -67,8 +67,8 @@ func BenchmarkWriter(b *testing.B) {
 			payload[i] = 'a'
 		}
 		for name, w := range map[string]io.WriteCloser{
-			"discard":          &NopWriteCloser{io.Discard},
-			"buffered-discard": newBufferedWriteCloser(&NopWriteCloser{io.Discard}),
+			"discard":          &nopWriteCloser{io.Discard},
+			"buffered-discard": newBufferedWriteCloser(&nopWriteCloser{io.Discard}),
 			"raw-file":         tempfile(b),
 			"buffered-file":    newBufferedWriteCloser(tempfile(b)),
 		} {

exporter/fileexporter/file_exporter_test.go

@@ -778,7 +778,7 @@ func TestFlushing(t *testing.T) {
 
 	// Create a buffer to capture the output.
 	bbuf := &tsBuffer{b: &bytes.Buffer{}}
-	buf := &NopWriteCloser{bbuf}
+	buf := &nopWriteCloser{bbuf}
 	// Wrap the buffer with the buffered writer closer that implements flush() method.
 	bwc := newBufferedWriteCloser(buf)
 	// Create a file exporter with flushing enabled.
@@ -833,7 +833,7 @@ func TestAppend(t *testing.T) {
 
 	// Create a buffer to capture the output.
 	bbuf := &tsBuffer{b: &bytes.Buffer{}}
-	buf := &NopWriteCloser{bbuf}
+	buf := &nopWriteCloser{bbuf}
 	// Wrap the buffer with the buffered writer closer that implements flush() method.
 	bwc := newBufferedWriteCloser(buf)
 	// Create a file exporter with flushing enabled.