diff --git a/call_test.go b/call_test.go
new file mode 100644
index 0000000..ad1c750
--- /dev/null
+++ b/call_test.go
@@ -0,0 +1,196 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package grpc
+
+import (
+	"io"
+	"math"
+	"net"
+	"strconv"
+	"sync"
+	"testing"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/transport"
+)
+
+var (
+	expectedRequest  = "ping"
+	expectedResponse = "pong"
+)
+
+type testCodec struct {
+}
+
+func (testCodec) Marshal(v interface{}) ([]byte, error) {
+	return []byte(*(v.(*string))), nil
+}
+
+func (testCodec) Unmarshal(data []byte, v interface{}) error {
+	*(v.(*string)) = string(data)
+	return nil
+}
+
+func (testCodec) String() string {
+	return "test"
+}
+
+type testStreamHandler struct {
+	t transport.ServerTransport
+}
+
+func (h *testStreamHandler) handleStream(t *testing.T, s *transport.Stream) {
+	p := &parser{s: s}
+	for {
+		pf, req, err := p.recvMsg()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("Failed to receive the message from the client.")
+		}
+		if pf != compressionNone {
+			t.Fatalf("Received the mistaken message format %d, want %d", pf, compressionNone)
+		}
+		var v string
+		codec := testCodec{}
+		if err := codec.Unmarshal(req, &v); err != nil {
+			t.Fatalf("Failed to unmarshal the received message %v", err)
+		}
+		if v != expectedRequest {
+			t.Fatalf("handleStream got %v, want %v", v, expectedRequest)
+		}
+	}
+	// send a response back to end the stream.
+	reply, err := encode(testCodec{}, &expectedResponse, compressionNone)
+	if err != nil {
+		t.Fatalf("Failed to encode the response: %v", err)
+	}
+	h.t.Write(s, reply, &transport.Options{})
+	h.t.WriteStatus(s, codes.OK, "")
+}
+
+type server struct {
+	lis  net.Listener
+	port string
+	// channel to signal server is ready to serve.
+	readyChan chan bool
+	mu        sync.Mutex
+	conns     map[transport.ServerTransport]bool
+}
+
+// start starts server. Other goroutines should block on s.readyChan for futher operations.
+func (s *server) start(t *testing.T, port int, maxStreams uint32) {
+	var err error
+	if port == 0 {
+		s.lis, err = net.Listen("tcp", ":0")
+	} else {
+		s.lis, err = net.Listen("tcp", ":"+strconv.Itoa(port))
+	}
+	if err != nil {
+		t.Fatalf("failed to listen: %v", err)
+	}
+	_, p, err := net.SplitHostPort(s.lis.Addr().String())
+	if err != nil {
+		t.Fatalf("failed to parse listener address: %v", err)
+	}
+	s.port = p
+	s.conns = make(map[transport.ServerTransport]bool)
+	if s.readyChan != nil {
+		close(s.readyChan)
+	}
+	for {
+		conn, err := s.lis.Accept()
+		if err != nil {
+			return
+		}
+		st, err := transport.NewServerTransport("http2", conn, maxStreams, nil)
+		if err != nil {
+			return
+		}
+		s.mu.Lock()
+		if s.conns == nil {
+			s.mu.Unlock()
+			st.Close()
+			return
+		}
+		s.conns[st] = true
+		s.mu.Unlock()
+		h := &testStreamHandler{st}
+		go st.HandleStreams(func(s *transport.Stream) {
+			go h.handleStream(t, s)
+		})
+	}
+}
+
+func (s *server) wait(t *testing.T, timeout time.Duration) {
+	select {
+	case <-s.readyChan:
+	case <-time.After(timeout):
+		t.Fatalf("Timed out after %v waiting for server to be ready", timeout)
+	}
+}
+
+func (s *server) stop() {
+	s.lis.Close()
+	s.mu.Lock()
+	for c := range s.conns {
+		c.Close()
+	}
+	s.conns = nil
+	s.mu.Unlock()
+}
+
+func setUp(t *testing.T, port int, maxStreams uint32) (*server, *ClientConn) {
+	server := &server{readyChan: make(chan bool)}
+	go server.start(t, port, maxStreams)
+	server.wait(t, 2*time.Second)
+	addr := "localhost:" + server.port
+	cc, err := Dial(addr, WithBlock(), WithInsecure(), WithCodec(testCodec{}))
+	if err != nil {
+		t.Fatalf("Failed to create ClientConn: %v", err)
+	}
+	return server, cc
+}
+
+func TestInvoke(t *testing.T) {
+	server, cc := setUp(t, 0, math.MaxUint32)
+	var reply string
+	if err := Invoke(context.Background(), "/foo/bar", &expectedRequest, &reply, cc); err != nil || reply != expectedResponse {
+		t.Fatalf("grpc.Invoke(_, _, _, _, _) = %v, want <nil>", err)
+	}
+	server.stop()
+}