Add testcases for IPC and basic focus switching

testcases/t/05-ipc.t

@@ -0,0 +1,51 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+
+use Test::More tests => 4;
+use Test::Deep;
+use X11::XCB qw(:all);
+use Data::Dumper;
+use Time::HiRes qw(sleep);
+use FindBin;
+use lib "$FindBin::Bin/lib";
+use i3test;
+
+BEGIN {
+    use_ok('IO::Socket::UNIX') or BAIL_OUT('Cannot load IO::Socket::UNIX');
+    use_ok('X11::XCB::Connection') or BAIL_OUT('Cannot load X11::XCB::Connection');
+}
+
+X11::XCB::Connection->connect(':0');
+
+my $sock = IO::Socket::UNIX->new(Peer => '/tmp/i3-ipc.sock');
+
+isa_ok($sock, 'IO::Socket::UNIX');
+
+
+#####################################################################
+# Ensure IPC works by switching workspaces
+#####################################################################
+
+# Switch to the first workspace to get a clean testing environment
+$sock->write(i3test::format_ipc_command("1"));
+
+sleep(0.25);
+
+# Create a window so we can get a focus different from NULL
+my $window = i3test::open_standard_window;
+diag("window->id = " . $window->id);
+
+sleep(0.25);
+
+my $focus = X11::XCB::Connection->input_focus;
+diag("old focus = $focus");
+
+# Switch to the nineth workspace
+$sock->write(i3test::format_ipc_command("9"));
+
+sleep(0.25);
+
+my $new_focus = X11::XCB::Connection->input_focus;
+isnt($focus, $new_focus, "Focus changed");
+
+diag( "Testing i3, Perl $], $^X" );