diff --git a/session_test.go b/session_test.go
index 227be291b..6dda633fc 100644
--- a/session_test.go
+++ b/session_test.go
@@ -17,20 +17,29 @@ import (
 	"github.com/lucas-clemente/quic-go/utils"
 )
 
-type mockConnection struct{}
+type mockConnection struct {
+	written [][]byte
+}
+
+func (m *mockConnection) write(p []byte) error {
+	m.written = append(m.written, p)
+	return nil
+}
 
-func (*mockConnection) write(p []byte) error                  { return nil }
 func (*mockConnection) setCurrentRemoteAddr(addr interface{}) {}
 
 var _ = Describe("Session", func() {
 	var (
 		session        *Session
 		callbackCalled bool
+		conn           *mockConnection
 	)
 
 	BeforeEach(func() {
+		conn = &mockConnection{}
 		callbackCalled = false
 		session = &Session{
+			conn:           conn,
 			streams:        make(map[protocol.StreamID]*stream),
 			streamCallback: func(*Session, utils.Stream) { callbackCalled = true },
 		}
@@ -178,7 +187,7 @@ var _ = Describe("Session", func() {
 			signer, err := crypto.NewRSASigner(path+"cert.der", path+"key.der")
 			Expect(err).ToNot(HaveOccurred())
 			scfg := handshake.NewServerConfig(crypto.NewCurve25519KEX(), signer)
-			session = NewSession(&mockConnection{}, 0, 0, scfg, nil).(*Session)
+			session = NewSession(conn, 0, 0, scfg, nil).(*Session)
 			go session.Run()
 			Expect(runtime.NumGoroutine()).To(Equal(nGoRoutinesBefore + 2))
 		})
@@ -204,4 +213,35 @@ var _ = Describe("Session", func() {
 			Expect(err).To(Equal(testErr))
 		})
 	})
+
+	Context("sending packets", func() {
+		BeforeEach(func() {
+			path := os.Getenv("GOPATH") + "/src/github.com/lucas-clemente/quic-go/example/"
+			signer, err := crypto.NewRSASigner(path+"cert.der", path+"key.der")
+			Expect(err).ToNot(HaveOccurred())
+			scfg := handshake.NewServerConfig(crypto.NewCurve25519KEX(), signer)
+			session = NewSession(conn, 0, 0, scfg, nil).(*Session)
+		})
+
+		It("sends ack frames", func() {
+			session.receivedPacketHandler.ReceivedPacket(1, true)
+			err := session.sendPacket()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(conn.written).To(HaveLen(1))
+			Expect(conn.written[0]).To(ContainSubstring(string([]byte{0x4c, 0x2, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0})))
+		})
+
+		It("sends queued stream frames", func() {
+			session.QueueStreamFrame(&frames.StreamFrame{
+				StreamID: 1,
+				Data:     []byte("foobar"),
+			})
+			session.receivedPacketHandler.ReceivedPacket(1, true)
+			err := session.sendPacket()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(conn.written).To(HaveLen(1))
+			Expect(conn.written[0]).To(ContainSubstring(string([]byte{0x4c, 0x2, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0})))
+			Expect(conn.written[0]).To(ContainSubstring(string("foobar")))
+		})
+	})
 })