diff --git a/README.md b/README.md
index 0102d30..bc663c3 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ server usage example:
 
 	cert, err := tls.LoadX509KeyPair("testdata/server.crt", "testdata/server.key")
 	if err != nil {
-		t.Fatal(err)
+		log.Fatal(err)
 	}
 
 	l, err := tls.Listen("tcp", "127.0.0.1:1100", &tls.Config{
@@ -18,7 +18,7 @@ server usage example:
 		NextProtos:   []string{"h2"},
 	})
 	if err != nil {
-		t.Fatal(err)
+		log.Fatal(err)
 	}
 	defer l.Close()
 	addr := l.Addr().String()
@@ -30,7 +30,7 @@ server usage example:
 		hdr.Set("aa", "bb")
 		d, err := ioutil.ReadAll(r.Body)
 		if err != nil {
-			ln(err)
+			log.Println(err)
 			return
 		}
 		w.Write(d)
@@ -43,7 +43,7 @@ server usage example:
 		}
 		h2conn, err := NewServerConn(c, nil)
 		if err != nil {
-			t.Fatal(err)
+			log.Fatal(err)
 		}
 		f("%+v", h2conn)
 		go h2conn.Run()
@@ -57,18 +57,18 @@ client usage example:
         ServerName: "nghttp2.org",
     })
     if err != nil {
-        t.Fatal(err)
+        log.Fatal(err)
     }
     defer conn.Close()
 
     cstate := conn.ConnectionState()
     if cstate.NegotiatedProtocol != "h2" {
-        t.Fatal("no http2 on server")
+        log.Fatal("no http2 on server")
     }
 
     h2conn, err := NewClientConn(conn)
     if err != nil {
-        t.Fatal(err)
+        log.Fatal(err)
     }
 
     param := url.Values{}
@@ -79,18 +79,18 @@ client usage example:
         "https://nghttp2.org/httpbin/post?a=b&c=d",
         data)
 
-    f("%+v", req)
+    log.Printf("%+v", req)
 
     req.Header.Set("user-agent", "go-nghttp2/1.0")
     req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 
     res, err := h2conn.CreateRequest(req)
     if err != nil {
-        t.Fatal(err)
+        log.Fatal(err)
     }
 
     if res.StatusCode != http.StatusOK {
-        t.Errorf("expect %d, got %d", http.StatusOK, res.StatusCode)
+        log.Printf("expect %d, got %d", http.StatusOK, res.StatusCode)
     }
     res.Write(os.Stderr)
 
@@ -99,7 +99,7 @@ co-work with net/http server example:
 
     l, err := net.Listen("tcp", "127.0.0.1:1222")
     if err != nil {
-        t.Fatal(err)
+        log.Fatal(err)
     }
     srv := &http.Server{
         TLSConfig: &tls.Config{