test: Add test for escaped semicolons in property parameters

Author: frereit

calendar_test.go

@@ -1,7 +1,6 @@
 package ics
 
 import (
-	"github.com/stretchr/testify/assert"
 	"io"
 	"io/ioutil"
 	"os"
@@ -11,6 +10,8 @@ import (
 	"testing"
 	"time"
 	"unicode/utf8"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestTimeParsing(t *testing.T) {
@@ -315,6 +316,31 @@ DESCRIPTION:blablablablablablablablablablablablablablablabltesttesttest
 CLASS:PUBLIC
 END:VEVENT
 END:VCALENDAR
+`,
+		},
+		{
+			name: "test semicolon in attendee property parameter",
+			input: `BEGIN:VCALENDAR
+VERSION:2.0
+X-CUSTOM-FIELD:test
+PRODID:-//arran4//Golang ICS Library
+DESCRIPTION:test
+BEGIN:VEVENT
+ATTENDEE;CN=Test\;User:mailto:user@example.com
+CLASS:PUBLIC
+END:VEVENT
+END:VCALENDAR
+`,
+			output: `BEGIN:VCALENDAR
+VERSION:2.0
+X-CUSTOM-FIELD:test
+PRODID:-//arran4//Golang ICS Library
+DESCRIPTION:test
+BEGIN:VEVENT
+ATTENDEE;CN=Test\;User:mailto:user@example.com
+CLASS:PUBLIC
+END:VEVENT
+END:VCALENDAR
 `,
 		},
 	}