Add support for custom validation rules

rules_test.go

@@ -1,9 +1,29 @@
 package validate
 
 import (
+	"reflect"
 	"testing"
 )
 
+func TestAddRule(t *testing.T) {
+	type s struct {
+		A string `validate:"custom"`
+	}
+
+	AddRule(`custom`, nil, Kinds{
+		reflect.String: func(rv reflect.Value, _ interface{}) bool {
+			return rv.String() == `custom`
+		},
+	})
+
+	var pass = s{`custom`}
+
+	var fail = s{`somethingelse`}
+
+	check(t, pass, 0)
+	check(t, fail, 1)
+}
+
 func TestRuleRequired(t *testing.T) {
 	type s struct {
 		A *string     `validate:"required"`