restart: make reply an array, add forgotten test to git (#3750)

related to #3565

testcases/t/305-restart-reply.t

@@ -0,0 +1,25 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • https://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • https://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • https://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Verify that restart produces a reply.
+# Ticket: #3565
+# Bug still in: 4.16-143-gca82f958
+use i3test;
+
+my $reply = cmd('restart');
+ok($reply->[0]->{success}, 'restart reply received');
+
+done_testing;