diff --git a/t/xe01_property.t b/t/xe01_property.t
deleted file mode 100644
index 6b894cd..0000000
--- a/t/xe01_property.t
+++ /dev/null
@@ -1,56 +0,0 @@
-
-use Test::More;
-use strict;
-
-BEGIN { plan tests => 90 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-
-use JSON;
-
-SKIP: {
-    skip "can't use JSON::XS.", 90, unless( JSON->backend->is_xs );
-
-my @simples = 
-    qw/ascii latin1 utf8 indent canonical space_before space_after allow_nonref shrink allow_blessed
-        convert_blessed relaxed
-     /;
-
-my $json = new JSON;
-
-for my $name (@simples) {
-    my $method = 'get_' . $name;
-    ok(! $json->$method(), $method . ' default');
-    $json->$name();
-    ok($json->$method(), $method . ' set true');
-    $json->$name(0);
-    ok(! $json->$method(), $method . ' set false');
-    $json->$name();
-    ok($json->$method(), $method . ' set true again');
-}
-
-
-ok($json->get_max_depth == 512, 'get_max_depth default');
-$json->max_depth(7);
-ok($json->get_max_depth == 7, 'get_max_depth set 7 => 7');
-$json->max_depth();
-ok($json->get_max_depth != 0, 'get_max_depth no arg');
-
-ok($json->get_max_size == 0, 'get_max_size default');
-$json->max_size(7);
-ok($json->get_max_size == 7, 'get_max_size set 7 => 7');
-$json->max_size();
-ok($json->get_max_size == 0, 'get_max_size no arg');
-
-
-for my $name (@simples) {
-    $json->$name();
-    ok($json->property($name), $name);
-    $json->$name(0);
-    ok(! $json->property($name), $name);
-    $json->$name();
-    ok($json->property($name), $name);
-}
-
-}
diff --git a/t/xe02_bool.t b/t/xe02_bool.t
deleted file mode 100644
index 1f0ddae..0000000
--- a/t/xe02_bool.t
+++ /dev/null
@@ -1,34 +0,0 @@
-#!/usr/bin/perl -w
-
-use strict;
-
-use Test::More;
-use strict;
-
-BEGIN { plan tests => 11 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON;
-
-SKIP: {
-    skip "can't use JSON::XS.", 11, unless( JSON->backend->is_xs );
-
-my $json = new JSON;
-
-is($json->encode([!1]),   '[""]');
-is($json->encode([!!2]), '["1"]');
-
-is($json->encode([ 'a' eq 'b'  ]), '[""]');
-is($json->encode([ 'a' eq 'a'  ]), '["1"]');
-
-is($json->encode([ ('a' eq 'b') + 1  ]), '[1]');
-is($json->encode([ ('a' eq 'a') + 1  ]), '[2]');
-
-ok(JSON::true eq 'true');
-ok(JSON::true eq  '1');
-ok(JSON::true == 1);
-isa_ok(JSON::true, JSON->backend . '::Boolean');
-isa_ok(JSON::true, 'JSON::Boolean');
-
-}
diff --git a/t/xe03_bool2.t b/t/xe03_bool2.t
deleted file mode 100644
index 7d68b32..0000000
--- a/t/xe03_bool2.t
+++ /dev/null
@@ -1,47 +0,0 @@
-use Test::More;
-
-BEGIN { plan tests => 26 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-use JSON;
-
-SKIP: {
-    skip "can't use JSON::XS.", 26, unless( JSON->backend->is_xs );
-
-is(to_json([JSON::true]),  q|[true]|);
-is(to_json([JSON::false]), q|[false]|);
-is(to_json([JSON::null]),  q|[null]|);
-
-my $jsontext = q|[true,false,null]|;
-my $obj      = from_json($jsontext);
-
-isa_ok($obj->[0], 'JSON::Boolean');
-isa_ok($obj->[1], 'JSON::Boolean');
-ok(!defined $obj->[2], 'null is undef');
-
-ok($obj->[0] == 1);
-ok($obj->[0] != 0);
-ok($obj->[1] == 0);
-ok($obj->[1] != 1);
-
-ok($obj->[0] eq 'true', 'eq true');
-ok($obj->[0] ne 'false', 'ne false');
-ok($obj->[1] eq 'false', 'eq false');
-ok($obj->[1] ne 'true', 'ne true');
-
-ok($obj->[0] eq $obj->[0]);
-ok($obj->[0] ne $obj->[1]);
-
-ok(JSON::true  eq 'true');
-ok(JSON::true  ne 'false');
-ok(JSON::true  ne 'null');
-ok(JSON::false eq 'false');
-ok(JSON::false ne 'true');
-ok(JSON::false ne 'null');
-ok(!defined JSON::null);
-
-is(from_json('[true]' )->[0], JSON::true);
-is(from_json('[false]')->[0], JSON::false);
-is(from_json('[null]' )->[0],  JSON::null);
-
-}
diff --git a/t/xe04support_by_pp.t b/t/xe04support_by_pp.t
deleted file mode 100644
index f8c8873..0000000
--- a/t/xe04support_by_pp.t
+++ /dev/null
@@ -1,22 +0,0 @@
-use strict;
-use Test::More;
-BEGIN { plan tests => 3 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -support_by_pp;
-
-SKIP: {
-    skip "can't use JSON::XS.", 3, unless( JSON->backend->is_xs );
-
-my $json = new JSON;
-
-
-is($json->escape_slash(0)->allow_nonref->encode("/"), '"/"');
-is($json->escape_slash(1)->allow_nonref->encode("/"), '"\/"');
-is($json->escape_slash(0)->allow_nonref->encode("/"), '"/"');
-
-
-}
-__END__
-
diff --git a/t/xe05_indent_length.t b/t/xe05_indent_length.t
deleted file mode 100644
index fc28fa3..0000000
--- a/t/xe05_indent_length.t
+++ /dev/null
@@ -1,76 +0,0 @@
-use strict;
-use Test::More;
-BEGIN { plan tests => 7 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -support_by_pp;
-
-SKIP: {
-    skip "can't use JSON::XS.", 7, unless( JSON->backend->is_xs );
-
-my $json = new JSON;
-
-
-is($json->indent_length(2)->encode([1,{foo => 'bar'}, "1", "/"]), qq|[1,{"foo":"bar"},"1","/"]|);
-
-is($json->indent->encode([1,{foo => 'bar'}, "1", "/"]), qq|[
-  1,
-  {
-    "foo":"bar"
-  },
-  "1",
-  "/"
-]
-|);
-
-
-is($json->escape_slash(1)->pretty->indent_length(2)->encode([1,{foo => 'bar'}, "1", "/"]), qq|[
-  1,
-  {
-    "foo" : "bar"
-  },
-  "1",
-  "\\/"
-]
-|);
-
-
-is($json->escape_slash(1)->pretty->indent_length(3)->encode([1,{foo => 'bar'}, "1", "/"]), qq|[
-   1,
-   {
-      "foo" : "bar"
-   },
-   "1",
-   "\\/"
-]
-|);
-
-is($json->escape_slash(1)->pretty->indent_length(15)->encode([1,{foo => 'bar'}, "1", "/"]), qq|[
-               1,
-               {
-                              "foo" : "bar"
-               },
-               "1",
-               "\\/"
-]
-|);
-
-
-is($json->indent_length(0)->encode([1,{foo => 'bar'}, "1", "/"]), qq|[
-1,
-{
-"foo" : "bar"
-},
-"1",
-"\\/"
-]
-|);
-
-is($json->indent(0)->space_before(0)->space_after(0)->escape_slash(0)
-        ->encode([1,{foo => 'bar'}, "1", "/"]), qq|[1,{"foo":"bar"},"1","/"]|);
-
-
-}
-
-
diff --git a/t/xe08_decode.t b/t/xe08_decode.t
deleted file mode 100644
index ed78fbb..0000000
--- a/t/xe08_decode.t
+++ /dev/null
@@ -1,45 +0,0 @@
-#
-# decode on Perl 5.005, 5.6, 5.8 or later
-#
-use strict;
-use Test::More;
-
-BEGIN { plan tests => 6 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON;
-
-BEGIN {
-    use lib qw(t);
-    use _unicode_handling;
-}
-
-no utf8;
-
-SKIP: {
-    skip "can't use JSON::XS.", 6, unless( JSON->backend->is_xs );
-
-my $json = JSON->new->allow_nonref;
-
-
-is($json->decode(q|"ü"|),                   "ü"); # utf8
-is($json->decode(q|"\u00fc"|),           "\xfc"); # latin1
-is($json->decode(q|"\u00c3\u00bc"|), "\xc3\xbc"); # utf8
-
-my $str = 'あ'; # Japanese 'a' in utf8
-
-is($json->decode(q|"\u00e3\u0081\u0082"|), $str);
-
-utf8::decode($str); # usually UTF-8 flagged on, but no-op for 5.005.
-
-is($json->decode(q|"\u3042"|), $str);
-
-
-my $utf8 = $json->decode(q|"\ud808\udf45"|); # chr 12345
-
-utf8::encode($utf8); # UTf-8 flaged off
-
-is($utf8, "\xf0\x92\x8d\x85");
-
-}
diff --git a/t/xe10_bignum.t b/t/xe10_bignum.t
deleted file mode 100644
index d72b8ad..0000000
--- a/t/xe10_bignum.t
+++ /dev/null
@@ -1,36 +0,0 @@
-
-use strict;
-use Test::More;
-BEGIN { plan tests => 6 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -support_by_pp;
-
-eval q| require Math::BigInt |;
-
-
-SKIP: {
-    skip "can't use JSON::XS.", 6, unless( JSON->backend->is_xs );
-    skip "Can't load Math::BigInt.", 6 if ($@);
-
-my $json = new JSON;
-print $json->backend, "\n";
-
-$json->allow_nonref->allow_bignum(1);
-$json->convert_blessed->allow_blessed;
-
-my $num  = $json->decode(q|100000000000000000000000000000000000000|);
-
-isa_ok($num, 'Math::BigInt');
-is($num, '100000000000000000000000000000000000000');
-is($json->encode($num), '100000000000000000000000000000000000000');
-
-$num  = $json->decode(q|2.0000000000000000001|);
-
-isa_ok($num, 'Math::BigFloat');
-is($num, '2.0000000000000000001');
-is($json->encode($num), '2.0000000000000000001');
-
-
-}
diff --git a/t/xe11_conv_blessed_univ.t b/t/xe11_conv_blessed_univ.t
deleted file mode 100644
index 8ccc0c1..0000000
--- a/t/xe11_conv_blessed_univ.t
+++ /dev/null
@@ -1,48 +0,0 @@
-
-use strict;
-use Test::More;
-BEGIN { plan tests => 3 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -convert_blessed_universally;
-
-SKIP: {
-    skip "can't use JSON::XS.", 3, unless( JSON->backend->is_xs );
-
-my $obj  = Test->new( [ 1, 2, {foo => 'bar'} ] );
-
-$obj->[3] = Test2->new( { a => 'b' } );
-
-my $json = JSON->new->allow_blessed->convert_blessed;
-
-is( $json->encode( $obj ), '[1,2,{"foo":"bar"},"hoge"]'  );
-
-$json->convert_blessed(0);
-
-is( $json->encode( $obj ), 'null' );
-
-$json->allow_blessed(0)->convert_blessed(1);
-
-is( $json->encode( $obj ), '[1,2,{"foo":"bar"},"hoge"]'  );
-
-}
-
-package Test;
-
-sub new {
-    bless $_[1], $_[0];
-}
-
-
-
-package Test2;
-
-sub new {
-    bless $_[1], $_[0];
-}
-
-sub TO_JSON {
-    "hoge";
-}
-
diff --git a/t/xe12_boolean.t b/t/xe12_boolean.t
deleted file mode 100644
index 1d790d5..0000000
--- a/t/xe12_boolean.t
+++ /dev/null
@@ -1,35 +0,0 @@
-
-use strict;
-use Test::More;
-
-BEGIN { plan tests => 4 };
-
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -support_by_pp;
-
-BEGIN {
-    use lib qw(t);
-    use _unicode_handling;
-}
-
-
-SKIP: {
-    skip "can't use JSON::XS.", 4, unless( JSON->backend->is_xs );
-
-my $json = new JSON;
-my $bool = $json->allow_nonref->decode('true');
-
-# it's normal
-isa_ok( $bool, 'JSON::Boolean' );
-is( $json->encode([ JSON::true ]), '[true]' );
-
-# make XS non support flag enable!
-$bool = $json->allow_singlequote->decode('true');
-
-isa_ok( $bool, 'JSON::Boolean' );
-is( $json->encode([ JSON::true ]), '[true]' );
-
-}
-
-__END__
diff --git a/t/xe19_xs_and_suportbypp.t b/t/xe19_xs_and_suportbypp.t
deleted file mode 100644
index f8ed824..0000000
--- a/t/xe19_xs_and_suportbypp.t
+++ /dev/null
@@ -1,34 +0,0 @@
-#! perl
-
-# https://rt.cpan.org/Public/Bug/Display.html?id=52847
-
-use strict;
-use Test::More;
-
-BEGIN { plan tests => 2 };
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON -support_by_pp;
-
-SKIP: {
-    skip "can't use JSON::XS.", 2, unless( JSON->backend->is_xs );
-
-    my $json = JSON->new->allow_barekey;
-
-    for (1..2) {
-        is_deeply( test($json, q!{foo:"foo"}!   ), {foo=>'foo'} );
-        JSON->new->allow_singlequote(0);
-    }
-}
-
-
-sub test {
-    my ($coder, $str) = @_;
-    my $rv;
-    return $rv if eval { $rv = $coder->decode($str); 1 };
-    chomp( my $e = $@ );
-    return "died with \"$e\"";
-};
-
-
-
diff --git a/t/xe20_croak_message.t b/t/xe20_croak_message.t
deleted file mode 100644
index 07ea8e6..0000000
--- a/t/xe20_croak_message.t
+++ /dev/null
@@ -1,22 +0,0 @@
-#! perl
-
-# https://rt.cpan.org/Public/Bug/Display.html?id=61708
-
-use strict;
-use Test::More;
-
-BEGIN { plan tests => 1 };
-BEGIN { $ENV{PERL_JSON_BACKEND} = 1; }
-
-use JSON; # currently it can't pass with -support_by_pp;
-
-
-SKIP: {
-    skip "can't use JSON::XS.", 1, unless( JSON->backend->is_xs );
-
-    my $json = JSON->new;
-
-    eval q{ $json->encode( undef ) };
-    like( $@, qr/line 1\./ );
-}
-