diff --git a/msgq/msgq_test.go b/msgq/msgq_test.go
new file mode 100644
index 000000000..37bd11643
--- /dev/null
+++ b/msgq/msgq_test.go
@@ -0,0 +1,94 @@
+package msgq
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/libp2p/go-libp2p-core/peer"
+)
+
+func TestNew(t *testing.T) {
+	tests := []struct {
+		name string
+		cap  int
+	}{
+		{"unbuffered", 0},
+		{"buffered10", 10},
+		{"buffered100", 100},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := New(tt.cap)
+			if cap(got.ch) != tt.cap {
+				t.Errorf("New() ch cap %d, want %d", cap(got.ch), tt.cap)
+			}
+		})
+	}
+}
+
+func TestQueue_AddMessage(t *testing.T) {
+	tests := []struct {
+		name string
+		cap  int
+	}{
+		{"unbuffered", 0},
+		{"buffered", 100},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			q := &Queue{ch: make(chan message, tt.cap)}
+			for i := 0; i < tt.cap+10; i++ {
+				var wantErr error
+				if i >= tt.cap {
+					wantErr = ErrRxOverrun
+				} else {
+					wantErr = nil
+				}
+				err := q.AddMessage([]byte{}, peer.ID(""))
+				if err != wantErr {
+					t.Fatalf("AddMessage() iter %d, error = %v, want %v",
+						i, err, wantErr)
+				}
+			}
+		})
+	}
+}
+
+type testMessageHandler struct {
+	t   *testing.T
+	seq int
+}
+
+func (h *testMessageHandler) HandleMessage(content []byte, sender peer.ID) {
+	got, want := string(content), fmt.Sprint(h.seq)
+	if got != want {
+		h.t.Errorf("out-of-sequence message %v, want %v", got, want)
+	}
+	h.seq++
+}
+
+func TestQueue_HandleMessages(t *testing.T) {
+	ch := make(chan message, 500)
+	for seq := 0; seq < cap(ch); seq++ {
+		ch <- message{content: []byte(fmt.Sprint(seq))}
+	}
+	close(ch)
+	q := &Queue{ch: ch}
+	q.HandleMessages(&testMessageHandler{t: t})
+}
+
+func TestQueue_Close(t *testing.T) {
+	q := &Queue{ch: make(chan message, 100)}
+	err := q.Close()
+	if err != nil {
+		t.Errorf("Close() error = %v, want nil", err)
+	}
+	select {
+	case m, ok := <-q.ch:
+		if ok {
+			t.Errorf("unexpected message %v", m)
+		}
+	default:
+		t.Error("channel closed but not ready")
+	}
+}