Specify default function length size

Enable linter funlen to limit the function length
and the number of the statements.

.golangci.yml

@@ -2,10 +2,15 @@ linters:
   disable-all: true
   enable:
     - bodyclose
+    - funlen
     - lll
     - misspell
 
 linters-settings:
+  funlen:
+    lines: 80
+    statements: 30
+
   lll:
     line-length: 100
     tab-width: 1

testhelper/upstream.go

@@ -0,0 +1,54 @@
+package testhelper
+
+import (
+	"net"
+	"testing"
+)
+
+type Upstream struct {
+	listener    net.Listener
+	logger      testing.TB
+	Connections chan net.Conn
+}
+
+func NewUpstream(t testing.TB, ignoreData bool) *Upstream {
+	result := &Upstream{}
+	result.listen()
+	result.accept(ignoreData)
+
+	return result
+}
+
+func (u *Upstream) listen() {
+	listener, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		u.logger.Fatalf("Failed to create TCP server: %v", err)
+	}
+	u.listener = listener
+}
+
+func (u *Upstream) accept(ignoreData bool) {
+	u.Connections = make(chan net.Conn)
+	go func(u *Upstream) {
+		conn, err := u.listener.Accept()
+		if err != nil {
+			u.logger.Fatalf("Unable to accept TCP connection: %v", err)
+		}
+		if ignoreData {
+			buf := make([]byte, 4000)
+			for err == nil {
+				_, err = conn.Read(buf)
+			}
+		} else {
+			u.Connections <- conn
+		}
+	}(u)
+}
+
+func (u *Upstream) Close() {
+	u.listener.Close()
+}
+
+func (u *Upstream) Addr() string {
+	return u.listener.Addr().String()
+}