diff --git a/protocol/rtcp/client.go b/protocol/rtcp/client.go
index 6659f349..654f56ae 100644
--- a/protocol/rtcp/client.go
+++ b/protocol/rtcp/client.go
@@ -138,6 +138,9 @@ func (c *client) send() {
 	}
 }
 
+// formPayload takes a pointer to a ReceiverReport and a pointer to a
+// Source Description and calls Bytes on both, writing to the underlying client
+// buf. A slice to the combined writtem memory is returned.
 func (c *client) formPayload(r *ReceiverReport, d *SourceDescription) []byte {
 	rl := len(r.Bytes(c.buf[:]))
 	dl := len(d.Bytes(c.buf[rl:]))
diff --git a/protocol/rtcp/client_test.go b/protocol/rtcp/client_test.go
index e566aa7c..cc10d4b9 100644
--- a/protocol/rtcp/client_test.go
+++ b/protocol/rtcp/client_test.go
@@ -1,5 +1,85 @@
 package rtcp
 
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"testing"
+)
+
+func TestFormPayload(t *testing.T) {
+	expect := []byte{
+		0x81, 0xc9, 0x00, 0x07,
+		0xd6, 0xe0, 0x98, 0xda,
+		0x6f, 0xad, 0x40, 0xc6,
+		0x00, 0xff, 0xff, 0xff,
+		0x00, 0x01, 0x83, 0x08,
+		0x00, 0x00, 0x00, 0x20,
+		0xb9, 0xe1, 0x25, 0x2a,
+		0x00, 0x00, 0x2b, 0xf9,
+		0x81, 0xca, 0x00, 0x04,
+		0xd6, 0xe0, 0x98, 0xda,
+		0x01, 0x08, 0x73, 0x61,
+		0x78, 0x6f, 0x6e, 0x2d,
+		0x70, 0x63, 0x00, 0x00,
+	}
+
+	report := ReceiverReport{
+		Header: Header{
+			Version:     2,
+			Padding:     false,
+			ReportCount: 1,
+			Type:        typeReceiverReport,
+		},
+		SenderSSRC: 3605043418,
+		Blocks: []ReportBlock{
+			ReportBlock{
+				SSRC:            1873625286,
+				FractionLost:    0,
+				PacketsLost:     math.MaxUint32,
+				HighestSequence: 99080,
+				Jitter:          32,
+				LSR:             3118540074,
+				DLSR:            11257,
+			},
+		},
+		Extensions: nil,
+	}
+
+	description := SourceDescription{
+		Header: Header{
+			Version:     2,
+			Padding:     false,
+			ReportCount: 1,
+			Type:        typeSourceDescription,
+		},
+		Chunks: []Chunk{
+			Chunk{
+				SSRC: 3605043418,
+				Items: []SDESItem{
+					SDESItem{
+						Type: typeCName,
+						Text: []byte("saxon-pc"),
+					},
+				},
+			},
+		},
+	}
+
+	c := &client{}
+	p := c.formPayload(&report, &description)
+
+	if !bytes.Equal(p, expect) {
+		t.Fatalf("unexpected result.\nGot: %v\n Want: %v\n", p, expect)
+	}
+
+	bufAddr := fmt.Sprintf("%p", c.buf[:])
+	pAddr := fmt.Sprintf("%p", p)
+	if bufAddr != pAddr {
+		t.Errorf("unexpected result.\nGot: %v\n want: %v\n", pAddr, bufAddr)
+	}
+}
+
 /*
 func TestReceiveAndSend(t *testing.T) {
 	quit := make(chan struct{})
@@ -24,4 +104,5 @@ func testServer(quit chan struct{}, t *testing.T) {
 	default:
 	}
 }
+
 */