fix: Fixes and performance improvements in utils package (#331)

backend/internal/utils/file_util_test.go

@@ -0,0 +1,73 @@
+package utils
+
+import (
+	"testing"
+)
+
+func TestGetFileExtension(t *testing.T) {
+	tests := []struct {
+		name     string
+		filename string
+		want     string
+	}{
+		{
+			name:     "Simple file with extension",
+			filename: "document.pdf",
+			want:     "pdf",
+		},
+		{
+			name:     "File with path",
+			filename: "/path/to/document.txt",
+			want:     "txt",
+		},
+		{
+			name:     "File with path (Windows style)",
+			filename: "C:\\path\\to\\document.jpg",
+			want:     "jpg",
+		},
+		{
+			name:     "Multiple extensions",
+			filename: "archive.tar.gz",
+			want:     "gz",
+		},
+		{
+			name:     "Hidden file with extension",
+			filename: ".config.json",
+			want:     "json",
+		},
+		{
+			name:     "Filename with dots",
+			filename: "version.1.2.3.txt",
+			want:     "txt",
+		},
+		{
+			name:     "File with uppercase extension",
+			filename: "image.JPG",
+			want:     "JPG",
+		},
+		{
+			name:     "File without extension",
+			filename: "README",
+			want:     "README",
+		},
+		{
+			name:     "Hidden file without extension",
+			filename: ".gitignore",
+			want:     "gitignore",
+		},
+		{
+			name:     "Empty filename",
+			filename: "",
+			want:     "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetFileExtension(tt.filename)
+			if got != tt.want {
+				t.Errorf("GetFileExtension(%q) = %q, want %q", tt.filename, got, tt.want)
+			}
+		})
+	}
+}