diff --git a/go/tests/capitalize_test/main.go b/go/tests/capitalize_test/main.go
index 6501097eb..bcc4b4a0a 100644
--- a/go/tests/capitalize_test/main.go
+++ b/go/tests/capitalize_test/main.go
@@ -12,12 +12,12 @@ import (
 func capitalize(s string) string {
 	r := []rune(strings.ToLower(s))
 
-	if unicode.IsLower(r[0]) {
+	if unicode.Is(unicode.Latin, r[0]) {
 		r[0] = unicode.ToUpper(r[0])
 	}
 
 	for i := 1; i < len(r); i++ {
-		if !unicode.Is(unicode.ASCII_Hex_Digit, r[i-1]) && unicode.IsLower(r[i]) {
+		if !unicode.IsDigit(r[i-1]) && !unicode.Is(unicode.Latin, r[i-1]) {
 			r[i] = unicode.ToUpper(r[i])
 		}
 	}