diff --git a/test/lazutils/testunicode.lpi b/test/lazutils/testunicode.lpi
index 363a2b3775..7a868b98be 100644
--- a/test/lazutils/testunicode.lpi
+++ b/test/lazutils/testunicode.lpi
@@ -6,7 +6,6 @@
       <Flags>
         <MainUnitHasCreateFormStatements Value="False"/>
         <MainUnitHasTitleStatement Value="False"/>
-        <UseDefaultCompilerOptions Value="True"/>
       </Flags>
       <SessionStorage Value="InProjectDir"/>
       <MainUnit Value="0"/>
@@ -57,6 +56,7 @@
     </SearchPaths>
     <Linking>
       <Debugging>
+        <GenerateDebugInfo Value="True"/>
         <DebugInfoType Value="dsAuto"/>
       </Debugging>
     </Linking>
diff --git a/test/lazutils/testunicode.pas b/test/lazutils/testunicode.pas
index 62a2f7d43a..b74a4f9a20 100644
--- a/test/lazutils/testunicode.pas
+++ b/test/lazutils/testunicode.pas
@@ -3,18 +3,54 @@ program TestUnicode;
 {$mode objfpc}{$H+}
 
 uses
-  lazutf8;
+  sysutils, lazutf8;
+
+procedure WriteStringHex(Str: utf8string);
+var
+  StrOut: utf8string;
+  i: Integer;
+begin
+  StrOut := '';
+  for i := 1 to Length(Str) do
+  begin
+    StrOut := StrOut + IntToHex(Byte(Str[i]), 2) + ' ';
+  end;
+  Write(StrOut);
+end;
 
 procedure AssertStringOperation(AMsg, AStr1, AStr2, AStrExpected2: utf8string);
 begin
-  Write(AMsg, ' ', AStr1, ' => ', AStr2, ' Expected ', AStrExpected2);
-  if UTF8CompareStr(AStr1, AStr2) <> 0 then Write(' !Error!');
+  Write(AMsg, ' ', AStr1, ' => ', AStr2);
+  if UTF8CompareStr(AStr1, AStr2) <> 0 then
+  begin
+    Write(' Expected ', AStrExpected2, ' !Error!');
+    WriteLn();
+    WriteStringHex(AStr2);
+    WriteLn('');
+    WriteLn('Expected');
+    WriteStringHex(AStr2);
+  end;
   WriteLn();
 end;
 
+procedure AssertStringOperationUTF8UpperCase(AMsg, ALocale, AStr1, AStrExpected2: utf8string);
 begin
+  AssertStringOperation(AMsg, AStr1, UTF8UpperCase(AStr1, ALocale), AStrExpected2);
+end;
+
+procedure TestUTF8UpperCase;
+begin
+  // ASCII
+  AssertStringOperationUTF8UpperCase('ASCII UTF8UpperCase', '', 'abcdefghijklmnopqrstuwvxyz', 'ABCDEFGHIJKLMNOPQRSTUWVXYZ');
+  // Latin
+  AssertStringOperationUTF8UpperCase('Polish UTF8UpperCase 1', '', 'aąbcćdeęfghijklłmnńoóprsśtuwyzźż', 'AĄBCĆDEĘFGHIJKLŁMNŃOÓPRSŚTUWYZŹŻ');
+  AssertStringOperationUTF8UpperCase('Polish UTF8UpperCase 2', '', 'AĄBCĆDEĘFGHIJKLŁMNŃOÓPRSŚTUWYZŹŻ', 'AĄBCĆDEĘFGHIJKLŁMNŃOÓPRSŚTUWYZŹŻ');
   // Turkish
-  AssertStringOperation('Turkish UTF8UpperCase 1', 'abcçdefgğhıijklmnoöprsştuüvyz', UTF8UpperCase('abcçdefgğhıijklmnoöprsştuüvyz'), 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ');
-  AssertStringOperation('Turkish UTF8UpperCase 2', 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ', UTF8UpperCase('ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ'), 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ');
+  AssertStringOperationUTF8UpperCase('Turkish UTF8UpperCase 1', 'tu', 'abcçdefgğhıijklmnoöprsştuüvyz', 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ');
+  AssertStringOperationUTF8UpperCase('Turkish UTF8UpperCase 2', 'tu', 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ', 'ABCÇDEFGĞHIİJKLMNOÖPRSŞTUÜVYZ');
+end;
+
+begin
+  TestUTF8UpperCase();
 end.