* t/format-ssa-event.t : check class inheritance

t/format-ssa-event.t

@@ -1,7 +1,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 30;
+use Test::More tests => 31;
 
 use Subtitle::Format::SSA::Event;
 
@@ -11,6 +11,7 @@ my ($fields, @fields, $format, $sample, $event, $output);
 $format = 'Format: Marked, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text';
 @fields = qw(marked start end style name marginl marginr marginv effect text);
 $event = Subtitle::Format::SSA::Event->new(type => 'ssa');
+can_ok($event, qw(new parse t_start t_end text));
 $fields = $event->parse_format_line($format);
 is(ref $fields, 'ARRAY');
 is_deeply($fields, \@fields);