is($msgs->[0]->{mid}, 'a-mid@b', 'message exists in history');
is(scalar @$msgs, 1, 'only one message in history');
is($ibx->mm->num_for('a-mid@b'), 2, 'exists with second article number');
is($msgs->[0]->{mid}, 'a-mid@b', 'message exists in history');
is(scalar @$msgs, 1, 'only one message in history');
is($ibx->mm->num_for('a-mid@b'), 2, 'exists with second article number');