add UTF-8 handling tests for PostalAddress escape and parse methods

Author: cpuschma

v3/postaladdress.go

@@ -43,16 +43,14 @@ func (p *PostalAddress) Escape() string {
 	builder := &strings.Builder{}
 
 	for _, line := range p.lines {
-		for i := range line {
-			char := line[i]
-
+		for _, char := range line {
 			switch char {
 			case '\\':
 				builder.WriteString("\\5C")
 			case '$':
 				builder.WriteString("\\24")
 			default:
-				builder.WriteByte(char)
+				builder.WriteRune(char)
 			}
 		}
 
@@ -65,8 +63,9 @@ func (p *PostalAddress) Escape() string {
 // ParsePostalAddress parses an RFC 4517 escaped postal address string into a PostalAddress object or returns an error.
 func ParsePostalAddress(escaped string) (*PostalAddress, error) {
 	lines := strings.Split(escaped, "$")
+	var parsedLines []string
 
-	for lineIndex, line := range lines {
+	for _, line := range lines {
 		if line == "" {
 			// Skip empty lines
 			continue
@@ -92,8 +91,8 @@ func ParsePostalAddress(escaped string) (*PostalAddress, error) {
 				builder.WriteByte(char)
 			}
 		}
-		lines[lineIndex] = builder.String()
+		parsedLines = append(parsedLines, builder.String())
 	}
 
-	return &PostalAddress{lines: lines}, nil
+	return &PostalAddress{lines: parsedLines}, nil
 }

v3/postaladdress_test.go

@@ -31,3 +31,55 @@ func TestPostalAddressRoundTrip(t *testing.T) {
 		})
 	}
 }
+
+func TestPostalAddressUTF8Handling(t *testing.T) {
+	testCases := []struct {
+		name     string
+		lines    []string
+		expected string
+	}{
+		{
+			name:     "emoji characters",
+			lines:    []string{"123 Main St 🏠", "Tokyo 🗾", "Japan 🇯🇵"},
+			expected: "123 Main St 🏠$Tokyo 🗾$Japan 🇯🇵$",
+		},
+		{
+			name:     "cyrillic characters",
+			lines:    []string{"Красная площадь", "Москва 101000", "Россия"},
+			expected: "Красная площадь$Москва 101000$Россия$",
+		},
+		{
+			name:     "chinese characters",
+			lines:    []string{"北京市东城区", "天安门广场", "中国"},
+			expected: "北京市东城区$天安门广场$中国$",
+		},
+		{
+			name:     "arabic characters",
+			lines:    []string{"شارع الملك فهد", "الرياض", "المملكة العربية السعودية"},
+			expected: "شارع الملك فهد$الرياض$المملكة العربية السعودية$",
+		},
+		{
+			name:     "mixed scripts with special chars",
+			lines:    []string{"Café René ☕", "Zürich $1000\\month", "Schweiz 🇨🇭"},
+			expected: "Café René ☕$Zürich \\241000\\5Cmonth$Schweiz 🇨🇭$",
+		},
+		{
+			name:     "mathematical symbols",
+			lines:    []string{"∑ ∫ ∂", "π ≈ 3.14159", "∞ ≠ 0"},
+			expected: "∑ ∫ ∂$π ≈ 3.14159$∞ ≠ 0$",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			addr := NewPostalAddress(tc.lines)
+			escaped := addr.Escape()
+			assert.Equal(t, tc.expected, escaped, "UTF-8 characters should be preserved in escaped output")
+
+			// Round-trip test
+			parsed, err := ParsePostalAddress(escaped)
+			assert.NoError(t, err)
+			assert.Equal(t, tc.lines, parsed.Lines(), "UTF-8 characters should survive round-trip")
+		})
+	}
+}