diff --git a/testcases/lib/i3test.pm b/testcases/lib/i3test.pm
index 0f2f2e07..8437a534 100644
--- a/testcases/lib/i3test.pm
+++ b/testcases/lib/i3test.pm
@@ -144,6 +144,12 @@ sub wait_for_unmap {
 #
 # set dont_map to a true value to avoid mapping
 #
+# if you want to change aspects of your window before it would be mapped,
+# set before_map to a coderef. $window gets passed as $_ and as first argument.
+#
+# if you set both dont_map and before_map, the coderef will be called nevertheless
+#
+#
 # default values:
 #     class => WINDOW_CLASS_INPUT_OUTPUT
 #     rect => [ 0, 0, 30, 30 ]
@@ -152,10 +158,10 @@ sub wait_for_unmap {
 #     name => 'Window <n>'
 #
 sub open_window {
-    my ($args) = @_;
-    my %args = ($args ? %$args : ());
+    my %args = @_ == 1 ? %{$_[0]} : @_;
 
     my $dont_map = delete $args{dont_map};
+    my $before_map = delete $args{before_map};
 
     $args{class} //= WINDOW_CLASS_INPUT_OUTPUT;
     $args{rect} //= [ 0, 0, 30, 30 ];
@@ -165,6 +171,12 @@ sub open_window {
 
     my $window = $x->root->create_child(%args);
 
+    if ($before_map) {
+        # TODO: investigate why _create is not needed
+        $window->_create;
+        $before_map->($window) for $window;
+    }
+
     return $window if $dont_map;
 
     $window->map;
@@ -175,8 +187,7 @@ sub open_window {
 # Thin wrapper around open_window which sets window_type to
 # _NET_WM_WINDOW_TYPE_UTILITY to make the window floating.
 sub open_floating_window {
-    my ($args) = @_;
-    my %args = ($args ? %$args : ());
+    my %args = @_ == 1 ? %{$_[0]} : @_;
 
     $args{window_type} = $x->atom(name => '_NET_WM_WINDOW_TYPE_UTILITY');
 
@@ -323,17 +334,10 @@ sub sync_with_i3 {
     # one on the first call of sync_with_i3. It will be re-used in all
     # subsequent calls.
     if (!defined($_sync_window)) {
-        $_sync_window = $x->root->create_child(
-            class => WINDOW_CLASS_INPUT_OUTPUT,
-            rect => X11::XCB::Rect->new(x => -15, y => -15, width => 10, height => 10 ),
+        $_sync_window = open_window(
+            rect => [ -15, -15, 10, 10 ],
             override_redirect => 1,
-            background_color => '#ff0000',
-            event_mask => [ 'structure_notify' ],
         );
-
-        $_sync_window->map;
-
-        wait_for_event 2, sub { $_[0]->{response_type} == MAP_NOTIFY };
     }
 
     my $root = $x->get_root_window();
diff --git a/testcases/t/001-tile.t b/testcases/t/001-tile.t
index 460cbd90..c13b87c4 100644
--- a/testcases/t/001-tile.t
+++ b/testcases/t/001-tile.t
@@ -2,23 +2,16 @@
 # vim:ts=4:sw=4:expandtab
 
 use i3test;
-use X11::XCB 'WINDOW_CLASS_INPUT_OUTPUT';
 
 my $original_rect = X11::XCB::Rect->new(x => 0, y => 0, width => 30, height => 30);
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => $original_rect,
-    background_color => '#C0C0C0',
-);
-
+my $window = open_window(rect => $original_rect, dont_map => 1);
 isa_ok($window, 'X11::XCB::Window');
 
 is_deeply($window->rect, $original_rect, "rect unmodified before mapping");
 
 $window->map;
-
-sleep(0.25);
+wait_for_map $window;
 
 my $new_rect = $window->rect;
 ok(!eq_hash($new_rect, $original_rect), "Window got repositioned");
diff --git a/testcases/t/004-unmanaged.t b/testcases/t/004-unmanaged.t
index 70bdb557..e998eb46 100644
--- a/testcases/t/004-unmanaged.t
+++ b/testcases/t/004-unmanaged.t
@@ -2,15 +2,13 @@
 # vim:ts=4:sw=4:expandtab
 
 use i3test;
-use X11::XCB 'WINDOW_CLASS_INPUT_OUTPUT';
 
 my $original_rect = X11::XCB::Rect->new(x => 0, y => 0, width => 30, height => 30);
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
+my $window = open_window(
     rect => $original_rect,
     override_redirect => 1,
-    background_color => '#C0C0C0',
+    dont_map => 1,
 );
 
 isa_ok($window, 'X11::XCB::Window');
diff --git a/testcases/t/005-floating.t b/testcases/t/005-floating.t
index 6de3ea80..9ac45627 100644
--- a/testcases/t/005-floating.t
+++ b/testcases/t/005-floating.t
@@ -2,24 +2,12 @@
 # vim:ts=4:sw=4:expandtab
 
 use i3test;
-use X11::XCB 'WINDOW_CLASS_INPUT_OUTPUT';
 
 # Create a floating window which is smaller than the minimum enforced size of i3
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30],
-    background_color => '#C0C0C0',
-    # replace the type with 'utility' as soon as the coercion works again in X11::XCB
-    window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_UTILITY'),
-    event_mask => [ 'structure_notify' ],
-);
+my $window = open_floating_window;
 
 isa_ok($window, 'X11::XCB::Window');
 
-$window->map;
-
-wait_for_map $window;
-
 my ($absolute, $top) = $window->rect;
 
 ok($window->mapped, 'Window is mapped');
@@ -30,20 +18,10 @@ ok($absolute->{x} != 0 && $absolute->{y} != 0, 'i3 did not map it to (0x0)');
 
 $window->unmap;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 1, 1, 80, 90],
-    background_color => '#C0C0C0',
-    window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_UTILITY'),
-    event_mask => [ 'structure_notify' ],
-);
+$window = open_floating_window(rect => [ 1, 1, 80, 90 ]);
 
 isa_ok($window, 'X11::XCB::Window');
 
-$window->map;
-
-wait_for_map $window;
-
 ($absolute, $top) = $window->rect;
 
 cmp_ok($absolute->{width}, '==', 80, "i3 let the width at 80");
@@ -61,20 +39,10 @@ $window->unmap;
 # at least the size of its initial geometry
 #####################################################################
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 1, 1, 80, 90],
-    background_color => '#C0C0C0',
-    #window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_UTILITY'),
-    event_mask => [ 'structure_notify' ],
-);
+$window = open_window(rect => [ 1, 1, 80, 90 ]);
 
 isa_ok($window, 'X11::XCB::Window');
 
-$window->map;
-
-wait_for_map $window;
-
 cmd 'floating enable';
 sync_with_i3;
 
diff --git a/testcases/t/100-fullscreen.t b/testcases/t/100-fullscreen.t
index 4a8f87a7..cc893adc 100644
--- a/testcases/t/100-fullscreen.t
+++ b/testcases/t/100-fullscreen.t
@@ -2,7 +2,6 @@
 # vim:ts=4:sw=4:expandtab
 
 use i3test;
-use X11::XCB 'WINDOW_CLASS_INPUT_OUTPUT';
 use List::Util qw(first);
 
 my $i3 = i3(get_socket_path());
@@ -32,11 +31,9 @@ for my $o (@outputs) {
 
 my $original_rect = X11::XCB::Rect->new(x => 0, y => 0, width => 30, height => 30);
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
+my $window = open_window(
     rect => $original_rect,
-    background_color => '#C0C0C0',
-    event_mask => [ 'structure_notify' ],
+    dont_map => 1,
 );
 
 isa_ok($window, 'X11::XCB::Window');
@@ -83,11 +80,9 @@ $window->unmap;
 cmd 'open';
 
 $original_rect = X11::XCB::Rect->new(x => 0, y => 0, width => 30, height => 30);
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
+$window = open_window(
     rect => $original_rect,
-    background_color => 61440,
-    event_mask => [ 'structure_notify' ],
+    dont_map => 1,
 );
 
 is_deeply($window->rect, $original_rect, "rect unmodified before mapping");
@@ -114,11 +109,9 @@ ok(abs($wrect->{height} - $orect->{height}) < $threshold, 'height coordinate ful
 ###############################################################################
 
 $original_rect = X11::XCB::Rect->new(x => 0, y => 0, width => 30, height => 30);
-my $swindow = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
+my $swindow = open_window(
     rect => $original_rect,
-    background_color => '#C0C0C0',
-    event_mask => [ 'structure_notify' ],
+    dont_map => 1,
 );
 
 $swindow->map;
diff --git a/testcases/t/119-match.t b/testcases/t/119-match.t
index 2124c02e..e6a4e832 100644
--- a/testcases/t/119-match.t
+++ b/testcases/t/119-match.t
@@ -4,7 +4,7 @@
 # Tests all kinds of matching methods
 #
 use i3test;
-use X11::XCB qw(PROP_MODE_REPLACE WINDOW_CLASS_INPUT_OUTPUT);
+use X11::XCB qw(PROP_MODE_REPLACE);
 
 my $tmp = fresh_workspace;
 
@@ -69,31 +69,21 @@ sub set_wm_class {
     );
 }
 
-my $left = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
+sub open_special {
+    my %args = @_;
+    my $wm_class = delete($args{wm_class}) || 'special';
 
-$left->_create;
-set_wm_class($left->id, 'special', 'special');
-$left->name('left');
-$left->map;
-ok(wait_for_map($left), 'left window mapped');
+    return open_window(
+        %args,
+        before_map => sub { set_wm_class($_->id, $wm_class, $wm_class) },
+    );
+}
 
-my $right = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
+my $left = open_special(name => 'left');
+ok($left->mapped, 'left window mapped');
 
-$right->_create;
-set_wm_class($right->id, 'special', 'special');
-$right->name('right');
-$right->map;
-ok(wait_for_map($right), 'right window mapped');
+my $right = open_special(name => 'right');
+ok($right->mapped, 'right window mapped');
 
 # two windows should be here
 $content = get_ws_content($tmp);
@@ -112,18 +102,8 @@ is(@{$content}, 1, 'one window still there');
 
 $tmp = fresh_workspace;
 
-$left = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$left->_create;
-set_wm_class($left->id, 'special7', 'special7');
-$left->name('left');
-$left->map;
-ok(wait_for_map($left), 'left window mapped');
+$left = open_special(name => 'left', wm_class => 'special7');
+ok($left->mapped, 'left window mapped');
 
 # two windows should be here
 $content = get_ws_content($tmp);
@@ -142,18 +122,8 @@ is(@{$content}, 0, 'window killed');
 
 $tmp = fresh_workspace;
 
-$left = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$left->_create;
-set_wm_class($left->id, 'special7', 'special7');
-$left->name('ä 3');
-$left->map;
-ok(wait_for_map($left), 'left window mapped');
+$left = open_special(name => 'ä 3', wm_class => 'special7');
+ok($left->mapped, 'left window mapped');
 
 # two windows should be here
 $content = get_ws_content($tmp);
diff --git a/testcases/t/122-split.t b/testcases/t/122-split.t
index 3484c7fc..71736db4 100644
--- a/testcases/t/122-split.t
+++ b/testcases/t/122-split.t
@@ -4,7 +4,6 @@
 # Tests splitting
 #
 use i3test;
-use X11::XCB qw(:all);
 
 my $tmp = fresh_workspace;
 
diff --git a/testcases/t/127-regress-floating-parent.t b/testcases/t/127-regress-floating-parent.t
index 52b8b9c0..c83c0809 100644
--- a/testcases/t/127-regress-floating-parent.t
+++ b/testcases/t/127-regress-floating-parent.t
@@ -16,8 +16,7 @@ cmd 'open';
 my $floating = get_focused($tmp);
 diag("focused floating: " . get_focused($tmp));
 cmd 'mode toggle';
-# TODO: eliminate this race conditition
-sleep 1;
+sync_with_i3;
 
 # kill old container
 cmd qq|[con_id="$old"] focus|;
@@ -33,7 +32,7 @@ cmd 'kill';
 cmd qq|[con_id="$floating"] focus|;
 is(get_focused($tmp), $floating, 'floating window focused');
 
-sleep 1;
+sync_with_i3;
 cmd 'mode toggle';
 
 does_i3_live;
diff --git a/testcases/t/129-focus-after-close.t b/testcases/t/129-focus-after-close.t
index 3913f4c6..5fc3786e 100644
--- a/testcases/t/129-focus-after-close.t
+++ b/testcases/t/129-focus-after-close.t
@@ -42,9 +42,8 @@ isnt(get_focused($tmp), $second, 'different container focused');
 ##############################################################
 
 cmd 'kill';
-# TODO: this testcase sometimes has different outcomes when the
-# sleep is missing. why?
-sleep 0.25;
+sync_with_i3;
+
 ($nodes, $focus) = get_ws_content($tmp);
 is($nodes->[1]->{nodes}->[0]->{id}, $second, 'second container found');
 ok($nodes->[1]->{nodes}->[0]->{focused}, 'second container focused');
@@ -103,8 +102,7 @@ my $win = open_window({ background_color => '#00ff00' });
 
 cmd qq|[con_id="$middle"] focus|;
 $win->destroy;
-
-sleep 0.25;
+sync_with_i3;
 
 is(get_focused($tmp), $middle, 'middle container focused');
 
diff --git a/testcases/t/144-regress-floating-resize.t b/testcases/t/144-regress-floating-resize.t
index de33eeb3..03318d7a 100644
--- a/testcases/t/144-regress-floating-resize.t
+++ b/testcases/t/144-regress-floating-resize.t
@@ -11,23 +11,24 @@ use List::Util qw(sum);
 
 my $tmp = fresh_workspace;
 
-cmd 'exec /usr/bin/urxvt';
-sleep 0.5;
-cmd 'exec /usr/bin/urxvt';
-sleep 0.5;
+my $first = open_window;
+my $second = open_window;
+
 my ($nodes, $focus) = get_ws_content($tmp);
 my $old_sum = sum map { $_->{rect}->{width} } @{$nodes};
-#cmd 'open';
+
 cmd 'resize grow left 10 px or 25 ppt';
 cmd 'split v';
-#cmd 'open';
-cmd 'exec /usr/bin/urxvt';
-sleep 0.5;
-cmd 'mode toggle';
-sleep 0.5;
-cmd 'kill';
 
-sleep 0.5;
+sync_with_i3;
+
+my $third = open_window;
+
+cmd 'mode toggle';
+sync_with_i3;
+
+cmd 'kill';
+sync_with_i3;
 
 ($nodes, $focus) = get_ws_content($tmp);
 my $new_sum = sum map { $_->{rect}->{width} } @{$nodes};
diff --git a/testcases/t/147-regress-floatingmove.t b/testcases/t/147-regress-floatingmove.t
index ed85b57b..5a2c87d3 100644
--- a/testcases/t/147-regress-floatingmove.t
+++ b/testcases/t/147-regress-floatingmove.t
@@ -6,6 +6,11 @@
 #
 use i3test;
 
+sub sync_cmd {
+    cmd @_;
+    sync_with_i3;
+}
+
 my $tmp = fresh_workspace;
 
 my $left = open_window;
@@ -13,23 +18,19 @@ my $mid = open_window;
 my $right = open_window;
 
 # go to workspace level
-cmd 'level up';
-sleep 0.25;
+sync_cmd 'level up';
 
 # make it floating
-cmd 'mode toggle';
-sleep 0.25;
+sync_cmd 'mode toggle';
 
 # move the con outside the floating con
-cmd 'move up';
-sleep 0.25;
+sync_cmd 'move up';
 
 does_i3_live;
 
 # move another con outside
-cmd '[id="' . $mid->id . '"] focus';
-cmd 'move up';
-sleep 0.25;
+sync_cmd '[id="' . $mid->id . '"] focus';
+sync_cmd 'move up';
 
 does_i3_live;
 
diff --git a/testcases/t/148-regress-floatingmovews.t b/testcases/t/148-regress-floatingmovews.t
index 44d5a445..3d71b500 100644
--- a/testcases/t/148-regress-floatingmovews.t
+++ b/testcases/t/148-regress-floatingmovews.t
@@ -10,20 +10,18 @@ my $tmp = fresh_workspace;
 
 # open a tiling window on the first workspace
 open_window;
-#sleep 0.25;
 my $first = get_focused($tmp);
 
 # on a different ws, open a floating window
 my $otmp = fresh_workspace;
 open_window;
-#sleep 0.25;
 my $float = get_focused($otmp);
 cmd 'mode toggle';
-#sleep 0.25;
+sync_with_i3;
 
 # move the floating con to first workspace
 cmd "move workspace $tmp";
-#sleep 0.25;
+sync_with_i3;
 
 # switch to the first ws and check focus
 is(get_focused($tmp), $float, 'floating client correctly focused');
diff --git a/testcases/t/162-regress-dock-urgent.t b/testcases/t/162-regress-dock-urgent.t
index 7a0ac487..3562ba7a 100644
--- a/testcases/t/162-regress-dock-urgent.t
+++ b/testcases/t/162-regress-dock-urgent.t
@@ -5,7 +5,6 @@
 # found in 4be3178d4d360c2996217d811e61161c84d25898
 #
 use i3test;
-use X11::XCB 'WINDOW_CLASS_INPUT_OUTPUT';
 
 my $i3 = i3(get_socket_path());
 
@@ -22,17 +21,10 @@ is(@docked, 0, 'no dock clients yet');
 
 # open a dock client
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30],
-    background_color => '#FF0000',
+my $window = open_window(
     window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_DOCK'),
 );
 
-$window->map;
-
-sleep 0.25;
-
 #####################################################################
 # check that we can find it in the layout tree at the expected position
 #####################################################################
diff --git a/testcases/t/165-for_window.t b/testcases/t/165-for_window.t
index c7601809..0ca5bd11 100644
--- a/testcases/t/165-for_window.t
+++ b/testcases/t/165-for_window.t
@@ -4,7 +4,7 @@
 #
 #
 use i3test;
-use X11::XCB qw(PROP_MODE_REPLACE WINDOW_CLASS_INPUT_OUTPUT);
+use X11::XCB qw(PROP_MODE_REPLACE);
 
 ##############################################################
 # 1: test the following directive:
@@ -25,16 +25,7 @@ my $pid = launch_with_config($config);
 
 my $tmp = fresh_workspace;
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->name('Border window');
-$window->map;
-wait_for_map $window;
+my $window = open_window(name => 'Border window');
 
 my @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
@@ -47,14 +38,6 @@ wait_for_unmap $window;
 cmp_ok(@content, '==', 0, 'no more nodes');
 diag('content = '. Dumper(\@content));
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
 
 # TODO: move this to X11::XCB::Window
 sub set_wm_class {
@@ -75,10 +58,10 @@ sub set_wm_class {
     );
 }
 
-set_wm_class($window->id, 'borderless', 'borderless');
-$window->name('Borderless window');
-$window->map;
-wait_for_map $window;
+$window = open_window(
+    name => 'Borderless window',
+    before_map => sub { set_wm_class($_->id, 'borderless', 'borderless') },
+);
 
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
@@ -108,16 +91,7 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->name('special title');
-$window->map;
-wait_for_map $window;
+$window = open_window(name => 'special title');
 
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
@@ -168,16 +142,7 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->name('special mark title');
-$window->map;
-wait_for_map $window;
+$window = open_window(name => 'special mark title');
 
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
@@ -212,20 +177,11 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
+$window = open_window(
+    name => 'usethis',
+    before_map => sub { set_wm_class($_->id, 'borderless', 'borderless') },
 );
 
-$window->_create;
-
-set_wm_class($window->id, 'borderless', 'borderless');
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
-
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'none', 'no border');
@@ -268,20 +224,12 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
+
+$window = open_window(
+    name => 'usethis',
+    before_map => sub { set_wm_class($_->id, 'bar', 'foo') },
 );
 
-$window->_create;
-
-set_wm_class($window->id, 'bar', 'foo');
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
-
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'normal', 'normal border, not matched');
@@ -303,20 +251,11 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
+$window = open_window(
+    name => 'usethis',
+    before_map => sub { set_wm_class($_->id, 'bar', 'foo') },
 );
 
-$window->_create;
-
-set_wm_class($window->id, 'bar', 'foo');
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
-
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'none', 'no border');
@@ -340,20 +279,11 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
+$window = open_window(
+    name => 'usethis',
+    before_map => sub { set_wm_class($_->id, 'bar', 'foo') },
 );
 
-$window->_create;
-
-set_wm_class($window->id, 'bar', 'foo');
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
-
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'normal', 'normal border');
@@ -377,31 +307,24 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
+$window = open_window(
+    name => 'usethis',
+    before_map => sub {
+        my ($window) = @_;
+        my $atomname = $x->atom(name => 'WM_WINDOW_ROLE');
+        my $atomtype = $x->atom(name => 'STRING');
+        $x->change_property(
+            PROP_MODE_REPLACE,
+            $window->id,
+            $atomname->id,
+            $atomtype->id,
+            8,
+            length("i3test") + 1,
+            "i3test\x00"
+        );
+    },
 );
 
-$window->_create;
-
-my $atomname = $x->atom(name => 'WM_WINDOW_ROLE');
-my $atomtype = $x->atom(name => 'STRING');
-$x->change_property(
-  PROP_MODE_REPLACE,
-  $window->id,
-  $atomname->id,
-  $atomtype->id,
-  8,
-  length("i3test") + 1,
-  "i3test\x00"
-);
-
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
-
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'none', 'no border (window_role)');
@@ -426,25 +349,14 @@ $pid = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#00ff00',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-
-$window->name('usethis');
-$window->map;
-wait_for_map $window;
+$window = open_window(name => 'usethis');
 
 @content = @{get_ws_content($tmp)};
 cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'normal', 'normal border (window_role 2)');
 
-$atomname = $x->atom(name => 'WM_WINDOW_ROLE');
-$atomtype = $x->atom(name => 'STRING');
+my $atomname = $x->atom(name => 'WM_WINDOW_ROLE');
+my $atomtype = $x->atom(name => 'STRING');
 $x->change_property(
   PROP_MODE_REPLACE,
   $window->id,
diff --git a/testcases/t/166-assign.t b/testcases/t/166-assign.t
index a10516a6..254616c5 100644
--- a/testcases/t/166-assign.t
+++ b/testcases/t/166-assign.t
@@ -5,7 +5,7 @@
 # Tests if assignments work
 #
 use i3test;
-use X11::XCB qw(PROP_MODE_REPLACE WINDOW_CLASS_INPUT_OUTPUT);
+use X11::XCB qw(PROP_MODE_REPLACE);
 
 # TODO: move to X11::XCB
 sub set_wm_class {
@@ -26,6 +26,16 @@ sub set_wm_class {
     );
 }
 
+sub open_special {
+    my %args = @_;
+    my $wm_class = delete($args{wm_class}) || 'special';
+    $args{name} //= 'special window';
+
+    return open_window(
+        %args,
+        before_map => sub { set_wm_class($_->id, $wm_class, $wm_class) },
+    );
+}
 
 #####################################################################
 # start a window and see that it does not get assigned with an empty config
@@ -42,18 +52,7 @@ my $tmp = fresh_workspace;
 
 ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-wait_for_map $window;
+my $window = open_special;
 
 ok(@{get_ws_content($tmp)} == 1, 'special window got managed to current (random) workspace');
 
@@ -80,18 +79,7 @@ ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 my $workspaces = get_workspace_names;
 ok(!("targetws" ~~ @{$workspaces}), 'targetws does not exist yet');
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-wait_for_map $window;
+$window = open_special;
 
 ok(@{get_ws_content($tmp)} == 0, 'still no containers');
 ok("targetws" ~~ @{get_workspace_names()}, 'targetws exists');
@@ -120,21 +108,12 @@ $tmp = fresh_workspace;
 ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 ok("targetws" ~~ @{get_workspace_names()}, 'targetws does not exist yet');
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
 
 # We use sync_with_i3 instead of wait_for_map here because i3 will not actually
 # map the window -- it will be assigned to a different workspace and will only
 # be mapped once you switch to that workspace
+$window = open_special(dont_map => 1);
+$window->map;
 sync_with_i3;
 
 ok(@{get_ws_content($tmp)} == 0, 'still no containers');
@@ -161,18 +140,7 @@ ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 $workspaces = get_workspace_names;
 ok(!("targetws" ~~ @{$workspaces}), 'targetws does not exist yet');
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-wait_for_map $window;
+$window = open_special;
 
 my $content = get_ws($tmp);
 ok(@{$content->{nodes}} == 0, 'no tiling cons');
@@ -202,18 +170,7 @@ ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 $workspaces = get_workspace_names;
 ok(!("targetws" ~~ @{$workspaces}), 'targetws does not exist yet');
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-    event_mask => [ 'structure_notify' ],
-);
-
-$window->_create;
-set_wm_class($window->id, 'SPEcial', 'SPEcial');
-$window->name('special window');
-$window->map;
-wait_for_map $window;
+$window = open_special(wm_class => 'SPEcial');
 
 $content = get_ws($tmp);
 ok(@{$content->{nodes}} == 0, 'no tiling cons');
@@ -251,20 +208,10 @@ my @docked = get_dock_clients;
 # syntax
 is(@docked, 1, 'one dock client yet');
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
+$window = open_special(
     window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_DOCK'),
-    event_mask => [ 'structure_notify' ],
 );
 
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-wait_for_map $window;
-
 $content = get_ws($tmp);
 ok(@{$content->{nodes}} == 0, 'no tiling cons');
 ok(@{$content->{floating_nodes}} == 0, 'one floating con');
@@ -277,6 +224,4 @@ does_i3_live;
 
 exit_gracefully($pid);
 
-sleep 0.25;
-
 done_testing;
diff --git a/testcases/t/168-regress-fullscreen-restart.t b/testcases/t/168-regress-fullscreen-restart.t
index 74d284db..27812565 100644
--- a/testcases/t/168-regress-fullscreen-restart.t
+++ b/testcases/t/168-regress-fullscreen-restart.t
@@ -11,10 +11,10 @@ open_window;
 open_window;
 
 cmd 'layout stacking';
-sleep 1;
+sync_with_i3;
 
 cmd 'fullscreen';
-sleep 1;
+sync_with_i3;
 
 cmd 'restart';
 sleep 1;
diff --git a/testcases/t/173-regress-focus-assign.t b/testcases/t/173-regress-focus-assign.t
index bd0ff647..cf3385cc 100644
--- a/testcases/t/173-regress-focus-assign.t
+++ b/testcases/t/173-regress-focus-assign.t
@@ -6,7 +6,7 @@
 # assigned to an invisible workspace
 #
 use i3test;
-use X11::XCB qw(PROP_MODE_REPLACE WINDOW_CLASS_INPUT_OUTPUT);
+use X11::XCB qw(PROP_MODE_REPLACE);
 
 # TODO: move to X11::XCB
 sub set_wm_class {
@@ -27,6 +27,16 @@ sub set_wm_class {
     );
 }
 
+sub open_special {
+    my %args = @_;
+    my $wm_class = delete($args{wm_class}) || 'special';
+    $args{name} //= 'special window';
+
+    return open_window(
+        %args,
+        before_map => sub { set_wm_class($_->id, $wm_class, $wm_class) },
+    );
+}
 
 #####################################################################
 # start a window and see that it does not get assigned with an empty config
@@ -45,18 +55,7 @@ my $tmp = fresh_workspace;
 ok(@{get_ws_content($tmp)} == 0, 'no containers yet');
 ok(get_ws($tmp)->{focused}, 'current workspace focused');
 
-my $window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
-);
-
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-sleep 0.25;
-
+my $window = open_special;
 
 ok(@{get_ws_content($tmp)} == 0, 'special window not on current workspace');
 ok(@{get_ws_content('targetws')} == 1, 'special window on targetws');
@@ -66,20 +65,10 @@ ok(get_ws($tmp)->{focused}, 'current workspace still focused');
 # the same test, but with a floating window
 #####################################################################
 
-$window = $x->root->create_child(
-    class => WINDOW_CLASS_INPUT_OUTPUT,
-    rect => [ 0, 0, 30, 30 ],
-    background_color => '#0000ff',
+$window = open_special(
     window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_UTILITY'),
 );
 
-$window->_create;
-set_wm_class($window->id, 'special', 'special');
-$window->name('special window');
-$window->map;
-sleep 0.25;
-
-
 ok(@{get_ws_content($tmp)} == 0, 'special window not on current workspace');
 ok(@{get_ws_content('targetws')} == 1, 'special window on targetws');
 ok(get_ws($tmp)->{focused}, 'current workspace still focused');