Add leaktrace tests

perl/xt/leaks/leaktrace.t

@@ -0,0 +1,40 @@
+#!perl -w
+use strict;
+use Test::Requires 'Test::LeakTrace';
+use Test::More;
+
+use Data::MessagePack;
+
+my $data = {
+    a => 'foo',
+    b => 42,
+    c => undef,
+    d => [qw(bar baz)],
+    e => 3.14,
+};
+
+no_leaks_ok {
+    my $s = Data::MessagePack->pack($data);
+};
+
+no_leaks_ok {
+    eval { Data::MessagePack->pack([\*STDIN]) };
+    #note $@;
+    $@ or die "it must die";
+};
+
+my $s = Data::MessagePack->pack($data);
+
+no_leaks_ok {
+    my $data = Data::MessagePack->unpack($s);
+};
+
+no_leaks_ok {
+    my $ss = $s;
+    chop $ss;
+    eval { Data::MessagePack->unpack($ss) };
+    #note $@;
+    $@ or die "it must die";
+};
+
+done_testing;