diff --git a/mailboxes/t/run-tests.t b/mailboxes/t/run-tests.t
new file mode 100644
index 000000000..1b2a3d6f3
--- /dev/null
+++ b/mailboxes/t/run-tests.t
@@ -0,0 +1,98 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+use Test::More;
+use Cwd qw(abs_path);
+use File::Basename qw(dirname);
+use File::Path qw(make_path);
+use File::Temp qw(tempdir);
+
+my $root = abs_path(dirname(__FILE__)."/../..") or die "rootdir: $!";
+my $tmp = tempdir(CLEANUP => 1);
+
+our (%config, %userconfig, $module_config_directory, $module_var_directory,
+     $user_module_config_directory);
+$module_config_directory = "$tmp/config";
+$module_var_directory = "$tmp/var";
+make_path($module_config_directory, $module_var_directory);
+
+sub make_dir
+{
+my ($dir, $mode) = @_;
+make_path($dir, { mode => $mode });
+return -d $dir;
+}
+
+sub error
+{
+die join("", @_), "\n";
+}
+
+sub open_tempfile
+{
+my ($fh, $file) = @_;
+no strict 'refs';
+open($fh, $file) || die "open_tempfile $file: $!";
+}
+
+sub close_tempfile
+{
+my ($fh) = @_;
+no strict 'refs';
+close($fh) || die "close_tempfile: $!";
+}
+
+sub set_ownership_permissions
+{
+return 1;
+}
+
+require "$root/mailboxes/boxes-lib.pl";
+
+sub write_file
+{
+my ($file, $text) = @_;
+open(my $fh, ">", $file) || die "write $file: $!";
+print $fh $text;
+close($fh) || die "close $file: $!";
+}
+
+subtest 'count_maildir' => sub {
+	my $missing = "$tmp/missing/Maildir";
+	is(count_maildir($missing), 0, 'missing Maildir counts as empty');
+
+	my $maildir = "$tmp/user/Maildir";
+	make_path("$maildir/cur", "$maildir/new", "$maildir/tmp");
+	write_file("$maildir/cur/1", "Subject: one\n\nbody\n");
+	write_file("$maildir/new/2", "Subject: two\n\nbody\n");
+	write_file("$maildir/tmp/3", "Subject: temp\n\nbody\n");
+	is(count_maildir($maildir), 2, 'cur and new messages are counted');
+
+	my $broken = "$tmp/broken/Maildir";
+	make_path($broken);
+	my $ok = eval { count_maildir($broken); 1 };
+	ok(!$ok, 'malformed existing Maildir still fails');
+	like($@, qr/Failed to open \Q$broken\/cur\E/,
+	     'missing cur directory reports the existing error');
+
+	my $notdir = "$tmp/notdir/Maildir";
+	make_path("$tmp/notdir");
+	write_file($notdir, "not a maildir\n");
+	$ok = eval { count_maildir($notdir); 1 };
+	ok(!$ok, 'non-directory Maildir path still fails');
+	like($@, qr/Failed to open \Q$notdir\/cur\E/,
+	     'non-directory Maildir path reports the existing error');
+
+	SKIP: {
+		my $link = "$tmp/link/Maildir";
+		make_path("$tmp/link");
+		skip 'symlink unavailable', 2
+			if (!symlink("$tmp/no-such-target", $link));
+		$ok = eval { count_maildir($link); 1 };
+		ok(!$ok, 'dangling Maildir symlink still fails');
+		like($@, qr/Failed to open \Q$link\/cur\E/,
+		     'dangling Maildir symlink reports the existing error');
+		}
+	};
+
+done_testing();