diff --git a/packages/pastojs/tests/tcgenerics.pas b/packages/pastojs/tests/tcgenerics.pas
index 475ab9f667..e6b6022766 100644
--- a/packages/pastojs/tests/tcgenerics.pas
+++ b/packages/pastojs/tests/tcgenerics.pas
@@ -953,7 +953,7 @@ begin
     'rtl.createClass(this, "TBird$G2", this.TObject, function () {',
     '  this.$init = function () {',
     '    $mod.TObject.$init.call(this);',
-    '    this.F = "";',
+    '    this.F = "\x00";',
     '  };',
     '}, "TBird<System.Char>");',
     'this.w = null;',
diff --git a/packages/pastojs/tests/tcmodules.pas b/packages/pastojs/tests/tcmodules.pas
index 42c4d8e100..69660a1e49 100644
--- a/packages/pastojs/tests/tcmodules.pas
+++ b/packages/pastojs/tests/tcmodules.pas
@@ -3469,7 +3469,7 @@ begin
     LinesToStr([
     'this.i = 0;',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.b = false;',
     'this.d = 0.0;',
     'this.i2 = 3;',
@@ -3585,7 +3585,7 @@ begin
     'this.b = false;',
     'this.d = 0.0;',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     '']),
     LinesToStr([ // this.$main
     '$mod.i = $mod.i;',
@@ -3636,7 +3636,7 @@ begin
     'this.b = false;',
     'this.d = 0.0;',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     '']),
     LinesToStr([ // this.$main
     '$mod.i = $mod.i;',
@@ -5016,7 +5016,7 @@ begin
   CheckSource('TestProc_VarParamString',
     LinesToStr([ // statements
     'this.DoIt = function (vA,vB,vC) {',
-    '  var c = "";',
+    '  var c = "\x00";',
     '  vA = rtl.setCharAt(vA, 0, c);',
     '  vB.set(rtl.setCharAt(vB.get(), 1, c));',
     '  vC.set(rtl.setCharAt(vC.get(), 2, c));',
@@ -7417,7 +7417,7 @@ begin
     'this.LowChars = rtl.createSet(null, 97, 122);',
     'this.Chars = rtl.unionSet(this.LowChars, rtl.createSet(null, 65, 90));',
     'this.sc = rtl.createSet(1040, 1071);',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.s = "";',
     '']),
     LinesToStr([
@@ -8671,7 +8671,7 @@ begin
   ConvertProgram;
   CheckSource('TestChar_Compare',
     LinesToStr([
-    'this.c="";',
+    'this.c = "\x00";',
     'this.b = false;'
     ]),
     LinesToStr([
@@ -8714,7 +8714,7 @@ begin
   ConvertProgram;
   CheckSource('TestChar_BuiltInProcs',
     LinesToStr([
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.i = 0;',
     'this.s = "";'
     ]),
@@ -9005,7 +9005,7 @@ begin
   CheckSource('TestString_CharAt',
     LinesToStr([ // statements
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.b = false;'
     ]),
     LinesToStr([ // this.$main
@@ -9160,7 +9160,7 @@ begin
   CheckSource('TestCharSet_Custom',
     LinesToStr([ // statements
     'this.crg = "b";',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.crg2 = "m";',
     'this.s = {};',
     '']),
@@ -9204,8 +9204,8 @@ begin
     '};',
     'this.Run = function (c) {',
     '};',
-    'this.c = "";',
-    'this.wc = "";',
+    'this.c = "\x00";',
+    'this.wc = "\x00";',
     'this.w = 0;',
     '']),
     LinesToStr([ // this.$main
@@ -9246,7 +9246,7 @@ begin
   ConvertProgram;
   CheckSource('TestForCharDo',
     LinesToStr([ // statements
-    'this.c = "";']),
+    'this.c = "\x00";']),
     LinesToStr([ // this.$main
     'for (var $l = 97; $l <= 99; $l++) $mod.c = String.fromCharCode($l);',
     'for (var $l1 = $mod.c.charCodeAt(); $l1 >= 97; $l1--) $mod.c = String.fromCharCode($l1);',
@@ -9291,11 +9291,11 @@ begin
   CheckSource('TestForCharInDo',
     LinesToStr([ // statements
     'this.Foo = "foo";',
-    'this.c = "";',
-    'this.c2 = "";',
+    'this.c = "\x00";',
+    'this.c2 = "\x00";',
     'this.s = "";',
     'this.a1 = [];',
-    'this.a2 = rtl.arraySetLength(null, "", 3);',
+    'this.a2 = rtl.arraySetLength(null, "\x00", 3);',
     'this.soc = {};',
     'this.socr = {};',
     'this.cr = "a";',
@@ -10049,8 +10049,8 @@ begin
   ConvertProgram;
   CheckSource('TestCaseOfString',
     LinesToStr([ // statements
-    'this.s = "";',
-    'this.h = "";',
+    'this.s = "\x00";',
+    'this.h = "\x00";',
     '']),
     LinesToStr([ // $mod.$main
     'var $tmp = $mod.s;',
@@ -10421,13 +10421,13 @@ begin
   ConvertProgram;
   CheckSource('TestArray_StaticChar',
     LinesToStr([ // statements
-    'this.Arr = rtl.arraySetLength(null, "", 65536);',
-    'this.Arr2 = rtl.arraySetLength(null, "", 26);',
+    'this.Arr = rtl.arraySetLength(null, "\x00", 65536);',
+    'this.Arr2 = rtl.arraySetLength(null, "\x00", 26);',
     'this.Arr3 = ["p", "a", "s"];',
     'this.Arr4 = ["p", "a", "s"];',
     'this.Arr5 = ["ä", "ö"];',
     'this.Arr6 = ["ä", "ö"];',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.b = false;',
     '']),
     LinesToStr([ // $mod.$main
@@ -11279,7 +11279,7 @@ begin
   ConvertProgram;
   CheckSource('TestArray_ArrayOfCharAssignString',
     LinesToStr([ // statements
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.s = "";',
     'this.a = [];',
     'this.Run = function (a) {',
@@ -29870,7 +29870,7 @@ begin
     'this.s = "";',
     'this.b = false;',
     'this.d = 0.0;',
-    'this.c = "";',
+    'this.c = "\x00";',
     '']),
     LinesToStr([ // $mod.$main
     '$mod.i = rtl.trunc($mod.v);',
@@ -29984,7 +29984,7 @@ begin
     'this.s = "";',
     'this.b = false;',
     'this.d = 0.0;',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.m = undefined;',
     '']),
     LinesToStr([ // $mod.$main
@@ -30369,7 +30369,7 @@ begin
     'this.b = false;',
     'this.d = 0.0;',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     '']),
     LinesToStr([ // $mod.$main
     '$mod.v = $mod.DoIt($mod.v, $mod.v, {',
@@ -30935,7 +30935,7 @@ begin
     'this.DoIt$1 = function (v) {',
     '};',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.u = "";',
     '']),
     LinesToStr([ // $mod.$main
@@ -30971,7 +30971,7 @@ begin
     'this.DoIt$1 = function (v) {',
     '};',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     'this.u = "";',
     '']),
     LinesToStr([ // $mod.$main
@@ -31599,7 +31599,7 @@ begin
     '  this.$init = function () {',
     '    this.FPropA = "";',
     '    this.VarLI = 0;',
-    '    this.VarC = "";',
+    '    this.VarC = "\x00";',
     '    this.VarS = "";',
     '    this.VarD = 0.0;',
     '    this.VarB = false;',
@@ -33631,7 +33631,7 @@ begin
     LinesToStr([ // statements
     'this.Bar = "bar";',
     'this.s = "";',
-    'this.c = "";',
+    'this.c = "\x00";',
     '$mod.$resourcestrings = {',
     '  Red: {',
     '      org: "red"',
@@ -34546,7 +34546,7 @@ begin
     '  var ArrChar = rtl.arraySetLength(null, 0, 10);',
     '  var ArrByteChar = rtl.arraySetLength(null, 0, 256, 10);',
     '  var i = 0;',
-    '  var c = "";',
+    '  var c = "\x00";',
     '  var o = null;',
     '  i = rtl.rc(Arr[1], 1, 10);',
     '  i = rtl.rc(ArrByteChar[1][2], 1, 10);',
@@ -34663,7 +34663,7 @@ begin
     'this.DoIt = function (h) {',
     '  var s = "";',
     '  var i = 0;',
-    '  var c = "";',
+    '  var c = "\x00";',
     '  var o = null;',
     '  c = rtl.rcc(rtl.rcCharAt(s, 0), 0, 65535);',
     '  s = rtl.rcSetCharAt(s, i - 1, rtl.rcCharAt(s, i - 1));',