circbufwriter: Add tests

lib/circbufwriter/writer_test.go

@@ -0,0 +1,71 @@
+package circbufwriter
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"testing"
+
+	"github.com/hashicorp/nomad/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestWriter_NonBlockingWrite(t *testing.T) {
+	require := require.New(t)
+	var buf bytes.Buffer
+	w := New(&buf, 64)
+	n, err := w.Write([]byte("test"))
+	require.Equal(4, n)
+	require.NoError(err)
+
+	n, err = w.Write([]byte("test"))
+	require.Equal(4, n)
+	require.NoError(err)
+
+	testutil.WaitForResult(func() (bool, error) {
+		return "testtest" == buf.String(), fmt.Errorf("expected both writes")
+	}, func(err error) {
+		require.NoError(err)
+	})
+}
+
+type blockingWriter struct {
+	buf     bytes.Buffer
+	unblock <-chan struct{}
+}
+
+func (b *blockingWriter) Write(p []byte) (nn int, err error) {
+	<-b.unblock
+	return b.buf.Write(p)
+}
+
+func TestWriter_BlockingWrite(t *testing.T) {
+	require := require.New(t)
+	blockCh := make(chan struct{})
+	bw := &blockingWriter{unblock: blockCh}
+	w := New(bw, 64)
+
+	n, err := w.Write([]byte("test"))
+	require.Equal(4, n)
+	require.NoError(err)
+	require.Empty(bw.buf.Bytes())
+
+	n, err = w.Write([]byte("test"))
+	require.Equal(4, n)
+	require.NoError(err)
+	require.Empty(bw.buf.Bytes())
+	close(blockCh)
+
+	testutil.WaitForResult(func() (bool, error) {
+		return "testtest" == bw.buf.String(), fmt.Errorf("expected both writes")
+	}, func(err error) {
+		require.NoError(err)
+	})
+}
+
+func TestWriter_CloseClose(t *testing.T) {
+	require := require.New(t)
+	w := New(ioutil.Discard, 64)
+	require.NoError(w.Close())
+	require.NoError(w.Close())
+}