gistfile1.txt

#! /usr/bin/env perl
use Mojolicious::Lite;
use Test::More;
use Test::Mojo;

post '/' => sub {
  my $self = shift;
  my $ct = $self->req->upload('bin')->headers->content_type;
  my $out = defined $ct ? $ct : "ct undef";
  $self->render(text => $out);
};

my $t = Test::Mojo->new;
$t->post_ok( '/' => form => { bin => { file => 'foo.ear' } } )
  ->status_is(200)
  ->content_like(qr/ct undef/);

done_testing();