diff --git a/docs/userguide b/docs/userguide
index 0258e2ab..98242a9b 100644
--- a/docs/userguide
+++ b/docs/userguide
@@ -1951,6 +1951,9 @@ bindsym $mod+t floating toggle
 To change focus, you can use the +focus+ command. The following options are
 available:
 
+<criteria>::
+    Sets focus to the container that matches the specified criteria.
+    See <<command_criteria>>.
 left|right|up|down::
         Sets focus to the nearest container in the given direction.
 parent::
@@ -1970,6 +1973,7 @@ output::
 
 *Syntax*:
 ----------------------------------------------
+<criteria> focus
 focus left|right|down|up
 focus parent|child|floating|tiling|mode_toggle
 focus output left|right|up|down|primary|<output>
@@ -1977,6 +1981,9 @@ focus output left|right|up|down|primary|<output>
 
 *Examples*:
 -------------------------------------------------
+# Focus firefox
+bindsym $mod+F1 [class="Firefox"] focus
+
 # Focus container on the left, bottom, top, right
 bindsym $mod+j focus left
 bindsym $mod+k focus down
diff --git a/src/commands.c b/src/commands.c
index a9187866..162f0892 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -1250,6 +1250,20 @@ void cmd_focus_direction(I3_CMD, const char *direction) {
     ysuccess(true);
 }
 
+/*
+ * Focus a container and disable any other fullscreen container not permitting the focus.
+ *
+ */
+static void cmd_focus_force_focus(Con *con) {
+    /* Disable fullscreen container in workspace with container to be focused. */
+    Con *ws = con_get_workspace(con);
+    Con *fullscreen_on_ws = (focused && focused->fullscreen_mode == CF_GLOBAL) ? focused : con_get_fullscreen_con(ws, CF_OUTPUT);
+    if (fullscreen_on_ws && fullscreen_on_ws != con && !con_has_parent(con, fullscreen_on_ws)) {
+        con_disable_fullscreen(fullscreen_on_ws);
+    }
+    con_focus(con);
+}
+
 /*
  * Implementation of 'focus tiling|floating|mode_toggle'.
  *
@@ -1257,28 +1271,34 @@ void cmd_focus_direction(I3_CMD, const char *direction) {
 void cmd_focus_window_mode(I3_CMD, const char *window_mode) {
     DLOG("window_mode = %s\n", window_mode);
 
-    Con *ws = con_get_workspace(focused);
-    if (ws != NULL) {
-        if (strcmp(window_mode, "mode_toggle") == 0) {
-            if (con_inside_floating(focused))
-                window_mode = "tiling";
-            else
-                window_mode = "floating";
-        }
-        Con *current;
-        TAILQ_FOREACH(current, &(ws->focus_head), focused) {
-            if ((strcmp(window_mode, "floating") == 0 && current->type != CT_FLOATING_CON) ||
-                (strcmp(window_mode, "tiling") == 0 && current->type == CT_FLOATING_CON))
-                continue;
-
-            con_focus(con_descend_focused(current));
-            break;
-        }
+    bool to_floating = false;
+    if (strcmp(window_mode, "mode_toggle") == 0) {
+        to_floating = !con_inside_floating(focused);
+    } else if (strcmp(window_mode, "floating") == 0) {
+        to_floating = true;
+    } else if (strcmp(window_mode, "tiling") == 0) {
+        to_floating = false;
     }
 
-    cmd_output->needs_tree_render = true;
-    // XXX: default reply for now, make this a better reply
-    ysuccess(true);
+    Con *ws = con_get_workspace(focused);
+    Con *current;
+    bool success = false;
+    TAILQ_FOREACH(current, &(ws->focus_head), focused) {
+        if ((to_floating && current->type != CT_FLOATING_CON) ||
+            (!to_floating && current->type == CT_FLOATING_CON))
+            continue;
+
+        cmd_focus_force_focus(con_descend_focused(current));
+        success = true;
+        break;
+    }
+
+    if (success) {
+        cmd_output->needs_tree_render = true;
+        ysuccess(true);
+    } else {
+        yerror("Failed to find a %s container in workspace.", to_floating ? "floating" : "tiling");
+    }
 }
 
 /*
@@ -1335,13 +1355,6 @@ void cmd_focus(I3_CMD) {
         if (!ws)
             continue;
 
-        /* Check the fullscreen focus constraints. */
-        if (!con_fullscreen_permits_focusing(current->con)) {
-            LOG("Cannot change focus while in fullscreen mode (fullscreen rules).\n");
-            ysuccess(false);
-            return;
-        }
-
         /* In case this is a scratchpad window, call scratchpad_show(). */
         if (ws == __i3_scratch) {
             scratchpad_show(current->con);
@@ -1365,7 +1378,7 @@ void cmd_focus(I3_CMD) {
          * So we focus 'current' to make it the currently focused window of
          * the target workspace, then revert focus. */
         Con *currently_focused = focused;
-        con_focus(current->con);
+        cmd_focus_force_focus(current->con);
         con_focus(currently_focused);
 
         /* Now switch to the workspace, then focus */
diff --git a/src/con.c b/src/con.c
index 1de91d00..c9e2b6cf 100644
--- a/src/con.c
+++ b/src/con.c
@@ -2070,14 +2070,7 @@ bool con_fullscreen_permits_focusing(Con *con) {
 
     /* Allow it only if the container to be focused is contained within the
      * current fullscreen container. */
-    do {
-        if (con->parent == fs)
-            return true;
-        con = con->parent;
-    } while (con);
-
-    /* Focusing con would hide it behind a fullscreen window, disallow it. */
-    return false;
+    return con_has_parent(con, fs);
 }
 
 /*
diff --git a/testcases/lib/i3test/Test.pm b/testcases/lib/i3test/Test.pm
index 0253bc2d..552ae8b4 100644
--- a/testcases/lib/i3test/Test.pm
+++ b/testcases/lib/i3test/Test.pm
@@ -5,6 +5,7 @@ use base 'Test::Builder::Module';
 
 our @EXPORT = qw(
     is_num_children
+    is_num_fullscreen
     cmp_float
     does_i3_live
 );
@@ -59,6 +60,25 @@ sub is_num_children {
     $tb->is_num($got_num_children, $num_children, $name);
 }
 
+=head2 is_num_fullscreen($workspace, $expected, $test_name)
+
+Gets the number of fullscreen containers on the given workspace and verifies that
+they match the expected amount.
+
+  is_num_fullscreen('1', 0, 'no fullscreen containers on workspace 1');
+
+=cut
+sub is_num_fullscreen {
+    my ($workspace, $num_fullscreen, $name) = @_;
+    my $workspace_content = i3test::get_ws($workspace);
+    my $tb = $CLASS->builder;
+
+    my $nodes = scalar grep { $_->{fullscreen_mode} != 0 } @{$workspace_content->{nodes}->[0]->{nodes}};
+    my $cons = scalar grep { $_->{fullscreen_mode} != 0 } @{$workspace_content->{nodes}};
+    my $floating = scalar grep { $_->{fullscreen_mode} != 0 } @{$workspace_content->{floating_nodes}->[0]->{nodes}};
+    $tb->is_num($nodes + $cons + $floating, $num_fullscreen, $name);
+}
+
 =head2 cmp_float($a, $b)
 
 Compares floating point numbers C<$a> and C<$b> and returns true if they differ
diff --git a/testcases/t/100-fullscreen.t b/testcases/t/100-fullscreen.t
index f0d0b4c6..d817bee0 100644
--- a/testcases/t/100-fullscreen.t
+++ b/testcases/t/100-fullscreen.t
@@ -21,13 +21,6 @@ my $i3 = i3(get_socket_path());
 
 my $tmp = fresh_workspace;
 
-sub fullscreen_windows {
-    my $ws = $tmp;
-    $ws = shift if @_;
-
-    scalar grep { $_->{fullscreen_mode} != 0 } @{get_ws_content($ws)}
-}
-
 # get the output of this workspace
 my $tree = $i3->get_tree->recv;
 my @outputs = @{$tree->{nodes}};
@@ -143,11 +136,11 @@ ok(!eq_hash($new_rect, $original_rect), "Window got repositioned");
 $swindow->fullscreen(1);
 sync_with_i3;
 
-is(fullscreen_windows(), 1, 'amount of fullscreen windows');
+is_num_fullscreen($tmp, 1, 'amount of fullscreen windows');
 
 $window->fullscreen(0);
 sync_with_i3;
-is(fullscreen_windows(), 1, 'amount of fullscreen windows');
+is_num_fullscreen($tmp, 1, 'amount of fullscreen windows');
 
 ok($swindow->mapped, 'window mapped after other fullscreen ended');
 
@@ -160,15 +153,15 @@ ok($swindow->mapped, 'window mapped after other fullscreen ended');
 $swindow->fullscreen(0);
 sync_with_i3;
 
-is(fullscreen_windows(), 0, 'amount of fullscreen windows after disabling');
+is_num_fullscreen($tmp, 0, 'amount of fullscreen windows after disabling');
 
 cmd 'fullscreen';
 
-is(fullscreen_windows(), 1, 'amount of fullscreen windows after fullscreen command');
+is_num_fullscreen($tmp, 1, 'amount of fullscreen windows after fullscreen command');
 
 cmd 'fullscreen';
 
-is(fullscreen_windows(), 0, 'amount of fullscreen windows after fullscreen command');
+is_num_fullscreen($tmp, 0, 'amount of fullscreen windows after fullscreen command');
 
 # clean up the workspace so that it will be cleaned when switching away
 cmd 'kill' for (@{get_ws_content($tmp)});
@@ -221,18 +214,18 @@ $swindow = open_window;
 
 cmd 'fullscreen';
 
-is(fullscreen_windows($tmp2), 1, 'one fullscreen window on second ws');
+is_num_fullscreen($tmp2, 1, 'one fullscreen window on second ws');
 
 cmd "move workspace $tmp";
 
-is(fullscreen_windows($tmp2), 0, 'no fullscreen windows on second ws');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on first ws');
+is_num_fullscreen($tmp2, 0, 'no fullscreen windows on second ws');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on first ws');
 
 $swindow->fullscreen(0);
 sync_with_i3;
 
 # Verify that $swindow was the one that initially remained fullscreen.
-is(fullscreen_windows($tmp), 0, 'no fullscreen windows on first ws');
+is_num_fullscreen($tmp, 0, 'no fullscreen windows on first ws');
 
 ################################################################################
 # Verify that opening a window with _NET_WM_STATE_FULLSCREEN unfullscreens any
@@ -245,14 +238,14 @@ $window = open_window();
 
 cmd "fullscreen";
 
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on ws');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on ws');
 is($x->input_focus, $window->id, 'fullscreen window focused');
 
 $swindow = open_window({
     fullscreen => 1
 });
 
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on ws');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on ws');
 is($x->input_focus, $swindow->id, 'fullscreen window focused');
 
 ################################################################################
@@ -263,19 +256,19 @@ $tmp = fresh_workspace;
 
 $window = open_window;
 is($x->input_focus, $window->id, 'window focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 cmd 'fullscreen enable';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 cmd 'fullscreen enable';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 1, 'still one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'still one fullscreen window on workspace');
 
 $window->fullscreen(0);
 sync_with_i3;
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 ################################################################################
 # Verify that command ‘fullscreen enable global’ works and is idempotent.
@@ -285,19 +278,19 @@ $tmp = fresh_workspace;
 
 $window = open_window;
 is($x->input_focus, $window->id, 'window focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 cmd 'fullscreen enable global';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 cmd 'fullscreen enable global';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 1, 'still one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'still one fullscreen window on workspace');
 
 $window->fullscreen(0);
 sync_with_i3;
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 ################################################################################
 # Verify that command ‘fullscreen disable’ works and is idempotent.
@@ -307,19 +300,19 @@ $tmp = fresh_workspace;
 
 $window = open_window;
 is($x->input_focus, $window->id, 'window focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 $window->fullscreen(1);
 sync_with_i3;
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 cmd 'fullscreen disable';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 cmd 'fullscreen disable';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 0, 'still no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'still no fullscreen window on workspace');
 
 ################################################################################
 # Verify that command ‘fullscreen toggle’ works.
@@ -328,15 +321,15 @@ is(fullscreen_windows($tmp), 0, 'still no fullscreen window on workspace');
 $tmp = fresh_workspace;
 
 $window = open_window;
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 cmd 'fullscreen toggle';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 cmd 'fullscreen toggle';
 is($x->input_focus, $window->id, 'window still focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 ################################################################################
 # Verify that a window’s fullscreen is disabled when another one is enabled
@@ -349,15 +342,15 @@ $window = open_window;
 $other = open_window;
 
 is($x->input_focus, $other->id, 'other window focused');
-is(fullscreen_windows($tmp), 0, 'no fullscreen window on workspace');
+is_num_fullscreen($tmp, 0, 'no fullscreen window on workspace');
 
 cmd 'fullscreen enable';
 is($x->input_focus, $other->id, 'other window focused');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 cmd '[id="' . $window->id . '"] fullscreen enable';
 is($x->input_focus, $window->id, 'window focused');
-is(fullscreen_windows($tmp), 1, 'one fullscreen window on workspace');
+is_num_fullscreen($tmp, 1, 'one fullscreen window on workspace');
 
 ################################################################################
 # Verify that when a global fullscreen is enabled the window is focused and
diff --git a/testcases/t/156-fullscreen-focus.t b/testcases/t/156-fullscreen-focus.t
index 7a5e38ca..cfa2405e 100644
--- a/testcases/t/156-fullscreen-focus.t
+++ b/testcases/t/156-fullscreen-focus.t
@@ -157,9 +157,6 @@ isnt($x->input_focus, $right2->id, 'bottom right window no longer focused');
 cmd 'focus child';
 is($x->input_focus, $right2->id, 'bottom right window focused again');
 
-cmd '[id="' . $left->id . '"] focus';
-is($x->input_focus, $right2->id, 'prevented focus change to left window');
-
 cmd 'focus up';
 is($x->input_focus, $right1->id, 'allowed focus up');
 
@@ -178,9 +175,6 @@ is($x->input_focus, $right1->id, 'allowed focus wrap (down)');
 cmd 'focus up';
 is($x->input_focus, $right2->id, 'allowed focus wrap (up)');
 
-cmd '[id="' . $diff_ws->id . '"] focus';
-is($x->input_focus, $right2->id, 'prevented focus change to different ws');
-
 ################################################################################
 # Same tests when we're in non-global fullscreen mode. It should now be possible
 # to focus a container in a different workspace.
@@ -202,9 +196,6 @@ isnt($x->input_focus, $right2->id, 'bottom right window no longer focused');
 cmd 'focus child';
 is($x->input_focus, $right2->id, 'bottom right window focused again');
 
-cmd '[id="' . $left->id . '"] focus';
-is($x->input_focus, $right2->id, 'prevented focus change to left window');
-
 cmd 'focus up';
 is($x->input_focus, $right1->id, 'allowed focus up');
 
@@ -323,6 +314,105 @@ verify_move(2, 'prevented move to workspace by name');
 cmd "move to workspace prev";
 verify_move(2, 'prevented move to workspace by position');
 
-# TODO: Tests for "move to output" and "move workspace to output".
+################################################################################
+# Ensure it's possible to focus a window using the focus command despite
+# fullscreen window blocking it. Fullscreen window should lose its fullscreen
+# mode.
+################################################################################
 
+# first & second tiling, focus using id
+kill_all_windows;
+
+$tmp = fresh_workspace;
+my $first = open_window;
+my $second = open_window;
+cmd 'fullscreen';
+is($x->input_focus, $second->id, 'fullscreen window focused');
+is_num_fullscreen($tmp, 1, '1 fullscreen window');
+
+cmd '[id="'. $first->id .'"] focus';
+sync_with_i3;
+
+is($x->input_focus, $first->id, 'correctly focused using id');
+is_num_fullscreen($tmp, 0, 'no fullscreen windows');
+
+# first floating, second tiling, focus using 'focus floating'
+kill_all_windows;
+
+$tmp = fresh_workspace;
+my $first = open_floating_window;
+my $second = open_window;
+cmd 'fullscreen';
+is($x->input_focus, $second->id, 'fullscreen window focused');
+is_num_fullscreen($tmp, 1, '1 fullscreen window');
+
+cmd 'focus floating';
+sync_with_i3;
+
+is($x->input_focus, $first->id, 'correctly focused using focus floating');
+is_num_fullscreen($tmp, 0, 'no fullscreen windows');
+
+# first tiling, second floating, focus using 'focus tiling'
+kill_all_windows;
+
+$tmp = fresh_workspace;
+my $first = open_window;
+my $second = open_floating_window;
+cmd 'fullscreen';
+is($x->input_focus, $second->id, 'fullscreen window focused');
+is_num_fullscreen($tmp, 1, '1 fullscreen window');
+
+cmd 'focus tiling';
+sync_with_i3;
+
+is($x->input_focus, $first->id, 'correctly focused using focus tiling');
+is_num_fullscreen($tmp, 0, 'no fullscreen windows');
+
+################################################################################
+# When the fullscreen window is in an other workspace it should maintain its
+# fullscreen mode since it's not blocking the window to be focused.
+################################################################################
+
+kill_all_windows;
+
+$tmp = fresh_workspace;
+my $first = open_window;
+
+$tmp2 = fresh_workspace;
+my $second = open_window;
+cmd 'fullscreen';
+is($x->input_focus, $second->id, 'fullscreen window focused');
+is_num_fullscreen($tmp2, 1, '1 fullscreen window');
+
+cmd '[id="'. $first->id .'"] focus';
+sync_with_i3;
+
+is($x->input_focus, $first->id, 'correctly focused using focus id');
+is_num_fullscreen($tmp, 0, 'no fullscreen windows on first workspace');
+is_num_fullscreen($tmp2, 1, 'still one fullscreen window on second workspace');
+
+################################################################################
+# But a global window in another workspace is blocking the window to be focused.
+# Ensure that it loses its fullscreen mode.
+################################################################################
+
+kill_all_windows;
+
+$tmp = fresh_workspace;
+$first = open_window;
+
+$tmp2 = fresh_workspace;
+$second = open_window;
+cmd 'fullscreen global';
+is($x->input_focus, $second->id, 'global window focused');
+is_num_fullscreen($tmp2, 1, '1 fullscreen window');
+
+cmd '[id="'. $first->id .'"] focus';
+sync_with_i3;
+
+is($x->input_focus, $first->id, 'correctly focused using focus id');
+is_num_fullscreen($tmp2, 0, 'no fullscreen windows');
+
+
+# TODO: Tests for "move to output" and "move workspace to output".
 done_testing;
diff --git a/testcases/t/206-fullscreen-scratchpad.t b/testcases/t/206-fullscreen-scratchpad.t
index c098f23f..95245099 100644
--- a/testcases/t/206-fullscreen-scratchpad.t
+++ b/testcases/t/206-fullscreen-scratchpad.t
@@ -21,15 +21,6 @@ use i3test;
 
 my $tmp = fresh_workspace;
 
-sub fullscreen_windows {
-    my $ws = $tmp;
-    $ws = shift if @_;
-
-    my $nodes = scalar grep { $_->{fullscreen_mode} != 0 } @{get_ws_content($ws)->[0]->{nodes}};
-    my $cons = scalar grep { $_->{fullscreen_mode} != 0 } @{get_ws_content($ws)};
-    return $nodes + $cons;
-}
-
 ##########################################################################################
 # map two windows in one container, fullscreen one of them and then move it to scratchpad
 ##########################################################################################
@@ -41,7 +32,7 @@ my $second_win = open_window;
 cmd 'fullscreen';
 
 # see if the window really is in fullscreen mode
-is(fullscreen_windows(), 1, 'amount of fullscreen windows after enabling fullscreen');
+is_num_fullscreen($tmp, 1, 'amount of fullscreen windows after enabling fullscreen');
 
 # move window to scratchpad
 cmd 'move scratchpad';
@@ -57,7 +48,7 @@ cmd 'scratchpad show';
 cmd 'floating toggle';
 
 # see if no window is in fullscreen mode
-is(fullscreen_windows(), 0, 'amount of fullscreen windows after showing previously fullscreened scratchpad window');
+is_num_fullscreen($tmp, 0, 'amount of fullscreen windows after showing previously fullscreened scratchpad window');
 
 ########################################################################################
 # move a window to scratchpad, focus parent container, make it fullscreen, focus a child
@@ -79,7 +70,7 @@ cmd 'fullscreen';
 cmd 'focus child';
 
 # see if the window really is in fullscreen mode
-is(fullscreen_windows(), 1, 'amount of fullscreen windows after enabling fullscreen on parent');
+is_num_fullscreen($tmp, 1, 'amount of fullscreen windows after enabling fullscreen on parent');
 
 ##########################################################################
 # show a scratchpad window; no window should be in fullscreen mode anymore
@@ -89,6 +80,6 @@ is(fullscreen_windows(), 1, 'amount of fullscreen windows after enabling fullscr
 cmd 'scratchpad show';
 
 # see if no window is in fullscreen mode
-is(fullscreen_windows(), 0, 'amount of fullscreen windows after showing a scratchpad window while a parent container was in fullscreen mode');
+is_num_fullscreen($tmp, 0, 'amount of fullscreen windows after showing a scratchpad window while a parent container was in fullscreen mode');
 
 done_testing;
diff --git a/testcases/t/291-swap.t b/testcases/t/291-swap.t
index d4a43bfb..3b61fdab 100644
--- a/testcases/t/291-swap.t
+++ b/testcases/t/291-swap.t
@@ -30,12 +30,6 @@ my ($result);
 my @fullscreen_permutations = ([], ["A"], ["B"], ["A", "B"]);
 my @urgent;
 
-sub fullscreen_windows {
-    my $ws = shift if @_;
-
-    scalar grep { $_->{fullscreen_mode} != 0 } @{get_ws_content($ws)}
-}
-
 ###############################################################################
 # Invalid con_id should not crash i3
 # See issue #2895.
@@ -191,14 +185,14 @@ for my $fullscreen (@fullscreen_permutations){
     $nodes = get_ws_content($ws1);
     $node = $nodes->[0];
     is($node->{window}, $B->{id}, 'B is on ws1:left');
-    is(fullscreen_windows($ws1), $A_fullscreen, 'amount of fullscreen windows in ws1');
+    is_num_fullscreen($ws1, $A_fullscreen, 'amount of fullscreen windows in ws1');
     is($node->{fullscreen_mode}, $A_fullscreen, 'B got A\'s fullscreen mode');
 
     $nodes = get_ws_content($ws2);
     $node = $nodes->[1];
     is($node->{window}, $A->{id}, 'A is on ws2:right');
     is(get_focused($ws2), $expected_focus, 'A is focused');
-    is(fullscreen_windows($ws2), $B_fullscreen, 'amount of fullscreen windows in ws2');
+    is_num_fullscreen($ws2, $B_fullscreen, 'amount of fullscreen windows in ws2');
     is($node->{fullscreen_mode}, $B_fullscreen, 'A got B\'s fullscreen mode');
 
     kill_all_windows;
@@ -232,7 +226,7 @@ cmd '[con_mark=B] swap container with mark A';
 
 $nodes = get_ws_content($ws1);
 is($nodes->[0]->{window}, $B->{id}, 'B is on ws1:left');
-is(fullscreen_windows($ws1), 1, 'F still fullscreen in ws1');
+is_num_fullscreen($ws1, 1, 'F still fullscreen in ws1');
 is(get_focused($ws1), $expected_focus, 'F is still focused');
 
 $nodes = get_ws_content($ws2);
@@ -258,7 +252,6 @@ cmd "split v";
 open_window;
 cmd "focus parent";
 cmd "fullscreen enable";
-$F = fullscreen_windows($ws1);
 $expected_focus = get_focused($ws1);
 
 $ws2 = fresh_workspace;
@@ -274,11 +267,11 @@ does_i3_live;
 $nodes = get_ws_content($ws1);
 is($nodes->[1]->{nodes}->[0]->{window}, $B->{id}, 'B is on top right in ws1');
 is(get_focused($ws1), $expected_focus, 'The container of the stacked windows remains focused in ws1');
-is(fullscreen_windows($ws1), $F, 'Same amount of fullscreen windows in ws1');
+is_num_fullscreen($ws1, 1, 'Same amount of fullscreen windows in ws1');
 
 $nodes = get_ws_content($ws2);
 is($nodes->[0]->{window}, $A->{id}, 'A is on ws2');
-is(fullscreen_windows($ws2), 1, 'A is in fullscreen mode');
+is_num_fullscreen($ws2, 1, 'A is in fullscreen mode');
 
 ###############################################################################
 # Swap two non-focused containers within the same workspace.
@@ -351,13 +344,13 @@ for my $fullscreen (@fullscreen_permutations){
     $nodes = get_ws_content($ws1);
     $node = $nodes->[0];
     is($node->{window}, $B->{id}, 'B is on the first workspace');
-    is(fullscreen_windows($ws1), $A_fullscreen, 'amount of fullscreen windows in ws1');
+    is_num_fullscreen($ws1, $A_fullscreen, 'amount of fullscreen windows in ws1');
     is($node->{fullscreen_mode}, $A_fullscreen, 'B got A\'s fullscreen mode');
 
     $nodes = get_ws_content($ws2);
     $node = $nodes->[0];
     is($node->{window}, $A->{id}, 'A is on the second workspace');
-    is(fullscreen_windows($ws2), $B_fullscreen, 'amount of fullscreen windows in ws2');
+    is_num_fullscreen($ws2, $B_fullscreen, 'amount of fullscreen windows in ws2');
     is($node->{fullscreen_mode}, $B_fullscreen, 'A got B\'s fullscreen mode');
 
     is(get_focused($ws3), $expected_focus, 'F is still focused');