Use ordered hash for point hints

lib/MongoDB/Cursor.pm

@@ -405,7 +405,7 @@ sub hint {
     confess "cannot set hint after querying"
 	if $self->started_iterating;
     confess 'not a hash reference'
-	unless ref $index eq 'HASH';
+	unless ref $index eq 'HASH' || ref $index eq 'Tie::IxHash';
 
     $self->_ensure_special;
     $self->_query->{'$hint'} = $index;

t/cursor.t

@@ -19,7 +19,7 @@ if ($@) {
     plan skip_all => $@;
 }
 else {
-    plan tests => 74;
+    plan tests => 77;
 }
 
 my $db = $conn->get_database('test_database');
@@ -166,7 +166,7 @@ $cursor->reset;
 $exp = $cursor->limit(-20)->explain;
 is(20, $exp->{'n'});
 
-#hint
+# hint
 $cursor->reset;
 my $hinted = $cursor->hint({'x' => 1});
 is($hinted, $cursor);
@@ -183,6 +183,32 @@ eval {
 
 ok($@ =~ m/bad hint/);
 
+# ordered hint
+$cursor->reset;
+$hinted = $cursor->hint(Tie::IxHash->new('x' => 1));
+is($hinted, $cursor);
+
+$collection->drop;
+
+$collection->insert({'num' => 1, 'foo' => 1});
+
+$aok = 1;
+eval {
+    $collection->query->hint(Tie::IxHash->new('num' => 1, 'foo' => 1))->explain;
+    $aok = 0;
+};
+
+ok($@ =~ m/bad hint/);
+
+$collection->ensure_index(Tie::IxHash->new('num' => 1, 'foo' => 1));
+$aok = 1;
+eval {
+    $collection->find({num => 0, foo => 0})->hint(Tie::IxHash->new('num' => 1, 'foo' => 1))->explain;
+    $aok = 0;
+};
+
+ok($aok == 0);
+
 # MongoDB::Cursor::slave_okay
 $MongoDB::Cursor::slave_okay = 1;
 $cursor = $collection->query->next;