+# emulate preprocessing [[!tag numbers primes lucky]] on page "seven", causing
+# the "numbers" and "primes" tag pages to be auto-created
+IkiWiki::Plugin::tag::preprocess_tag(page => "seven", numbers => undef, primes => undef, lucky => undef);
+is($autofiles{"tags/lucky.mdwn"}{plugin}, "tag");
+is($autofiles{"tags/numbers.mdwn"}{plugin}, "tag");
+is($autofiles{"tags/primes.mdwn"}{plugin}, "tag");
+is_deeply([sort keys %autofiles], [qw(tags/lucky.mdwn tags/numbers.mdwn tags/primes.mdwn)]);
+
+ok(!-e "t/tmp/tags/lucky.mdwn");
+my (%pages, @del);
+IkiWiki::gen_autofile("tags/lucky.mdwn", \%pages, \@del);
+ok(! -s "t/tmp/tags/lucky.mdwn");
+ok(-s "t/tmp/.ikiwiki/transient/tags/lucky.mdwn");
+is_deeply(\%pages, {"t/tmp/tags/lucky" => 1});
+is_deeply(\@del, []);
+
+# generating an autofile that already exists does nothing
+%pages = @del = ();
+IkiWiki::gen_autofile("tags/numbers.mdwn", \%pages, \@del);
+is_deeply(\%pages, {});
+is_deeply(\@del, []);
+
+# generating an autofile that we just deleted does nothing
+%pages = ();
+@del = ('tags/primes.mdwn');
+IkiWiki::gen_autofile("tags/primes.mdwn", \%pages, \@del);
+is_deeply(\%pages, {});
+is_deeply(\@del, ['tags/primes.mdwn']);
+
+done_testing;