diff --git a/tests/0026.container/0004.string/to_c_lower_upper.cc b/tests/0026.container/0004.string/to_c_lower_upper.cc
index 98e1c0e4d..7b0b2595b 100644
--- a/tests/0026.container/0004.string/to_c_lower_upper.cc
+++ b/tests/0026.container/0004.string/to_c_lower_upper.cc
@@ -3,28 +3,28 @@
 
 int main()
 {
-    ::fast_io::u8string ustr(u8"abcdefwegeABCDwgwasfsa 325235 fhasdfhsdh"), 
-                        ustr_upper(ustr), 
-                        ustr_lower(ustr),
-                        numbers(u8"1234567890"), 
-                        symbols(u8"!@#$%^&*()"), 
-                        empty;
+	::fast_io::u8string ustr(u8"abcdefwegeABCDwgwasfsa 325235 fhasdfhsdh"),
+		ustr_upper(ustr),
+		ustr_lower(ustr),
+		numbers(u8"1234567890"),
+		symbols(u8"!@#$%^&*()"),
+		empty;
 
-    // Apply transformations
-    ::fast_io::char_category::ranges::to_c_upper(ustr_upper);
-    ::fast_io::char_category::ranges::to_c_lower(ustr_lower);
-    ::fast_io::char_category::ranges::to_c_upper(numbers);
-    ::fast_io::char_category::ranges::to_c_upper(symbols);
-    ::fast_io::char_category::ranges::to_c_upper(empty);
+	// Apply transformations
+	::fast_io::char_category::ranges::to_c_upper(ustr_upper);
+	::fast_io::char_category::ranges::to_c_lower(ustr_lower);
+	::fast_io::char_category::ranges::to_c_upper(numbers);
+	::fast_io::char_category::ranges::to_c_upper(symbols);
+	::fast_io::char_category::ranges::to_c_upper(empty);
 
-    // Print all results in one println
-    ::fast_io::io::println(::fast_io::u8c_stdout(), 
-        u8"Original: ", ustr, 
-        u8"\nUppercase: ", ustr_upper, 
-        u8"\nLowercase: ", ustr_lower, 
-        u8"\nNumbers (unchanged): ", numbers, 
-        u8"\nSymbols (unchanged): ", symbols, 
-        u8"\nEmpty string: ", empty);
+	// Print all results in one println
+	::fast_io::io::println(::fast_io::u8c_stdout(),
+						   u8"Original: ", ustr,
+						   u8"\nUppercase: ", ustr_upper,
+						   u8"\nLowercase: ", ustr_lower,
+						   u8"\nNumbers (unchanged): ", numbers,
+						   u8"\nSymbols (unchanged): ", symbols,
+						   u8"\nEmpty string: ", empty);
 
-    return 0;
+	return 0;
 }