Implement the tick event

This makes our tests less flaky, shorter, and more readable.

fixes #2988

testcases/lib/i3test.pm.in

@@ -47,6 +47,8 @@ our @EXPORT = qw(
     wait_for_unmap
     $x
     kill_all_windows
+    events_for
+    listen_for_binding
 );
 
 =head1 NAME
@@ -900,6 +902,86 @@ sub kill_all_windows {
     cmd '[title=".*"] kill';
 }
 
+=head2 events_for($subscribecb, [ $rettype ], [ $eventcbs ])
+
+Helper function which returns an array containing all events of type $rettype
+which were generated by i3 while $subscribecb was running.
+
+Set $eventcbs to subscribe to multiple event types and/or perform your own event
+aggregation.
+
+=cut
+sub events_for {
+    my ($subscribecb, $rettype, $eventcbs) = @_;
+
+    my @events;
+    $eventcbs //= {};
+    if (defined($rettype)) {
+	$eventcbs->{$rettype} = sub { push @events, shift };
+    }
+    my $subscribed = AnyEvent->condvar;
+    my $flushed = AnyEvent->condvar;
+    $eventcbs->{tick} = sub {
+	my ($event) = @_;
+	if ($event->{first}) {
+	    $subscribed->send($event);
+	} else {
+	    $flushed->send($event);
+	}
+    };
+    my $i3 = i3(get_socket_path(0));
+    $i3->connect->recv;
+    $i3->subscribe($eventcbs)->recv;
+    $subscribed->recv;
+    # Subscription established, run the callback.
+    $subscribecb->();
+    # Now generate a tick event, which we know we’ll receive (and at which point
+    # all other events have been received).
+    my $nonce = int(rand(255)) + 1;
+    $i3->send_tick($nonce);
+
+    my $tick = $flushed->recv;
+    $tester->is_eq($tick->{payload}, $nonce, 'tick nonce received');
+    return @events;
+}
+
+=head2 listen_for_binding($cb)
+
+Helper function to evaluate whether sending KeyPress/KeyRelease events via XTEST
+triggers an i3 key binding or not. Expects key bindings to be configured in the
+form “bindsym <binding> nop <binding>”, e.g.  “bindsym Mod4+Return nop
+Mod4+Return”.
+
+  is(listen_for_binding(
+      sub {
+          xtest_key_press(133); # Super_L
+          xtest_key_press(36); # Return
+          xtest_key_release(36); # Return
+          xtest_key_release(133); # Super_L
+          xtest_sync_with_i3;
+      },
+      ),
+     'Mod4+Return',
+     'triggered the "Mod4+Return" keybinding');
+
+=cut
+
+sub listen_for_binding {
+    my ($cb) = @_;
+    my $triggered = AnyEvent->condvar;
+    my @events = events_for(
+	$cb,
+	'binding');
+
+    $tester->is_eq(scalar @events, 1, 'Received precisely one event');
+    $tester->is_eq($events[0]->{change}, 'run', 'change is "run"');
+    # We look at the command (which is “nop <binding>”) because that is easier
+    # than re-assembling the string representation of $event->{binding}.
+    my $command = $events[0]->{binding}->{command};
+    $command =~ s/^nop //g;
+    return $command;
+}
+
 =head1 AUTHOR
 
 Michael Stapelberg <michael@i3wm.org>

testcases/lib/i3test/XTEST.pm

@@ -20,8 +20,6 @@ our @EXPORT = qw(
     xtest_key_release
     xtest_button_press
     xtest_button_release
-    listen_for_binding
-    start_binding_capture
     binding_events
 );
 
@@ -256,86 +254,6 @@ sub import {
 
 =cut
 
-my $i3;
-our @binding_events;
-
-=head2 start_binding_capture()
-
-Captures all binding events sent by i3 in the C<@binding_events> symbol, so
-that you can verify the correct number of binding events was generated.
-
-  my $pid = launch_with_config($config);
-  start_binding_capture;
-  # …
-  sync_with_i3;
-  is(scalar @i3test::XTEST::binding_events, 2, 'Received exactly 2 binding events');
-
-=cut
-
-sub start_binding_capture {
-    # Store a copy of each binding event so that we can count the expected
-    # events in test cases.
-    $i3 = i3(get_socket_path());
-    $i3->connect()->recv;
-    $i3->subscribe({
-        binding => sub {
-            my ($event) = @_;
-            @binding_events = (@binding_events, $event);
-        },
-    })->recv;
-}
-
-=head2 listen_for_binding($cb)
-
-Helper function to evaluate whether sending KeyPress/KeyRelease events via
-XTEST triggers an i3 key binding or not (with a timeout of 0.5s). Expects key
-bindings to be configured in the form “bindsym <binding> nop <binding>”, e.g.
-“bindsym Mod4+Return nop Mod4+Return”.
-
-  is(listen_for_binding(
-      sub {
-          xtest_key_press(133); # Super_L
-          xtest_key_press(36); # Return
-          xtest_key_release(36); # Return
-          xtest_key_release(133); # Super_L
-      },
-      ),
-     'Mod4+Return',
-     'triggered the "Mod4+Return" keybinding');
-
-=cut
-
-sub listen_for_binding {
-    my ($cb) = @_;
-    my $triggered = AnyEvent->condvar;
-    my $i3 = i3(get_socket_path());
-    $i3->connect()->recv;
-    $i3->subscribe({
-        binding => sub {
-            my ($event) = @_;
-            return unless $event->{change} eq 'run';
-            # We look at the command (which is “nop <binding>”) because that is
-            # easier than re-assembling the string representation of
-            # $event->{binding}.
-            $triggered->send($event->{binding}->{command});
-        },
-    })->recv;
-
-    my $t;
-    $t = AnyEvent->timer(
-        after => 0.5,
-        cb => sub {
-            $triggered->send('timeout');
-        }
-    );
-
-    $cb->();
-
-    my $recv = $triggered->recv;
-    $recv =~ s/^nop //g;
-    return $recv;
-}
-
 =head2 set_xkb_group($group)
 
 Changes the current XKB group from the default of 1 to C<$group>, which must be