From 12032df45ddc2bccb69a67a5efa59bce28281e9e Mon Sep 17 00:00:00 2001
From: Matt <carmodym2@gmail.com>
Date: Mon, 8 Nov 2021 22:36:17 -0500
Subject: [PATCH] UcFirst accounts for multi-byte leading characters

---
 helper.go       |  4 ++--
 stringy.go      |  2 +-
 stringy_test.go | 36 ++++++++++++++++++++++++++----------
 3 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/helper.go b/helper.go
index 53311ae..16d4a61 100644
--- a/helper.go
+++ b/helper.go
@@ -59,8 +59,8 @@ func replaceStr(input, search, replace, types string) string {
 }
 
 func ucfirst(val string) string {
-	for i, v := range val {
-		return string(unicode.ToUpper(v)) + val[i+1:]
+	for _, v := range val {
+		return string(unicode.ToUpper(v)) + val[len(string(v)):]
 	}
 	return ""
 }
diff --git a/stringy.go b/stringy.go
index 046edbe..49040c9 100644
--- a/stringy.go
+++ b/stringy.go
@@ -10,7 +10,7 @@ import (
 	"unicode"
 )
 
-// input is struct that holds input form user and result
+// input is struct that holds input from user and result
 type input struct {
 	Input  string
 	Result string
diff --git a/stringy_test.go b/stringy_test.go
index 715a2fd..208cacb 100644
--- a/stringy_test.go
+++ b/stringy_test.go
@@ -276,18 +276,34 @@ func TestInput_TeaseEmpty(t *testing.T) {
 }
 
 func TestInput_UcFirst(t *testing.T) {
-	str := New("this is test")
-	against := "This is test"
-	if val := str.UcFirst(); val != against {
-		t.Errorf("Expected: to be %s but got: %s", against, val)
+	tests := []struct {
+		name string
+		arg  string
+		want string
+	}{
+		{
+			name: "leading lowercase",
+			arg:  "test input",
+			want: "Test input",
+		},
+		{
+			name: "empty string",
+			arg:  "",
+			want: "",
+		},
+		{
+			name: "multi-byte leading character",
+			arg:  "δδδ",
+			want: "Δδδ",
+		},
 	}
-}
 
-func TestInput_EmptyUcFirst(t *testing.T) {
-	str := New("")
-	against := ""
-	if val := str.UcFirst(); val != against {
-		t.Errorf("Expected: to be %s but got: %s", against, val)
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := New(tt.arg).UcFirst(); got != tt.want {
+				t.Errorf("UcFirst(%v) = %v, want %v", tt.arg, got, tt.want)
+			}
+		})
 	}
 }