Add load balancing network dialer

mtglib/network/init_test.go

@@ -1,13 +1,32 @@
 package network_test
 
 import (
+	"context"
+	"net"
 	"net/http/httptest"
 	"strings"
 
 	"github.com/mccutchen/go-httpbin/httpbin"
+	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/suite"
 )
 
+type DialerMock struct {
+	mock.Mock
+}
+
+func (d *DialerMock) Dial(network, address string) (net.Conn, error) {
+	args := d.Called(network, address)
+
+	return args.Get(0).(net.Conn), args.Error(1)
+}
+
+func (d *DialerMock) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	args := d.Called(ctx, network, address)
+
+	return args.Get(0).(net.Conn), args.Error(1)
+}
+
 type HTTPServerTestSuite struct {
 	suite.Suite