Test more expected failures

Encoder/t/300_fail.t

@@ -2,14 +2,28 @@
 use strict;
 use warnings;
 use Sereal::Encoder;
-use Test::More tests => 2;
+use Test::More tests => 4;
 
+my $ok; my $err; my $out;
+
+# croak_on_bless test
 my $e = Sereal::Encoder->new({
     croak_on_bless => 1,
 });
-my $ok = eval{$e->encode(bless({}, "Foo")); 1};
-my $err = $@ || 'Zombie error';
+$ok = eval{$out = $e->encode(bless({}, "Foo")); 1};
+$err = $@ || 'Zombie error';
+
+ok(!$ok, "Object throws exception");
+ok($err =~ /object/i, 'Exception refers to object');
+
+$ok =  eval {$out = $e->encode({}); 1};
+ok($ok, "Non-blessed hash does not throw exception");
+
 
-ok(!$ok);
-ok($err =~ /object/);
+# test that code refs throw exception
+TODO: {
+    local $TODO = "Serializing CODE refs should probably fail instead of serializing to \\undef";
+    $ok = eval {$out = $e->encode(sub {}); 1};
+    ok(!$ok, "Code ref throws exception");
+}