bind: support multiple values (#2128)

Signed-off-by: Shengjing Zhu <i@zhsj.me>

caddyhttp/httpserver/plugin_test.go

@@ -15,6 +15,7 @@
 package httpserver
 
 import (
+	"reflect"
 	"strings"
 	"testing"
 
@@ -347,3 +348,28 @@ func TestHideCaddyfile(t *testing.T) {
 	}
 	t.Fatal("Caddyfile missing from HiddenFiles")
 }
+
+func TestGroupSiteConfigsByListenAddr(t *testing.T) {
+	cfg := []*SiteConfig{
+		{
+			ListenHosts: []string{"127.0.0.1", "::1"},
+		},
+		{
+			Addr: Address{
+				Port: "80",
+			},
+		},
+	}
+	groups, err := groupSiteConfigsByListenAddr(cfg)
+	if err != nil {
+		t.Fatal("Failed to group SiteConfigs by listen address")
+	}
+	actual := []string{}
+	for k := range groups {
+		actual = append(actual, k)
+	}
+	expected := []string{"127.0.0.1:" + Port, "[::1]:" + Port, ":80"}
+	if !reflect.DeepEqual(actual, expected) {
+		t.Errorf("Expected listen on %#v, but got %#v", expected, actual)
+	}
+}