diff --git a/generate-command-parser.pl b/generate-command-parser.pl
index 4c45b6ed..052e4c66 100755
--- a/generate-command-parser.pl
+++ b/generate-command-parser.pl
@@ -77,7 +77,7 @@ for my $line (@lines) {
             ($line =~ /
                 ^\s*                  # skip leading whitespace
                 ([a-z_]+ \s* = \s*|)  # optional identifier
-                (.*?) -> \s*          # token 
+                (.*?) -> \s*          # token
                 (.*)                  # optional action
              /x);
 
diff --git a/testcases/t/134-invalid-command.t b/testcases/t/134-invalid-command.t
index 4557bbda..c10771c8 100644
--- a/testcases/t/134-invalid-command.t
+++ b/testcases/t/134-invalid-command.t
@@ -14,7 +14,7 @@
 #
 # • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
 #   (unless you are already familiar with Perl)
-# 
+#
 #
 use i3test;
 
diff --git a/testcases/t/232-cmd-move-criteria.t b/testcases/t/232-cmd-move-criteria.t
index 54e7ce9c..312c9660 100644
--- a/testcases/t/232-cmd-move-criteria.t
+++ b/testcases/t/232-cmd-move-criteria.t
@@ -45,7 +45,7 @@ is($x->input_focus, $win3->{id}, 'it should not disturb focus');
 ###############################################################################
 
 # test all window types
-my %window_types = ( 
+my %window_types = (
     'normal'        => '_NET_WM_WINDOW_TYPE_NORMAL',
     'dialog'        => '_NET_WM_WINDOW_TYPE_DIALOG',
     'utility'       => '_NET_WM_WINDOW_TYPE_UTILITY',
diff --git a/testcases/t/240-focus-on-window-activation.t b/testcases/t/240-focus-on-window-activation.t
index 57060753..efcd5ca4 100644
--- a/testcases/t/240-focus-on-window-activation.t
+++ b/testcases/t/240-focus-on-window-activation.t
@@ -22,7 +22,7 @@ use List::Util qw(first);
 my ($config, $pid, $first, $second, $ws1, $ws2);
 
 sub send_net_active_window {
-    my ($id) = @_; 
+    my ($id) = @_;
 
     my $msg = pack "CCSLLLLLLL",
         X11::XCB::CLIENT_MESSAGE, # response_type
diff --git a/testcases/t/243-move-to-mark.t b/testcases/t/243-move-to-mark.t
index abc2b4c6..25d13333 100644
--- a/testcases/t/243-move-to-mark.t
+++ b/testcases/t/243-move-to-mark.t
@@ -31,7 +31,7 @@ my $_NET_WM_STATE_ADD = 1;
 my $_NET_WM_STATE_TOGGLE = 2;
 
 sub set_urgency {
-    my ($win, $urgent_flag) = @_; 
+    my ($win, $urgent_flag) = @_;
     my $msg = pack "CCSLLLLLL",
         X11::XCB::CLIENT_MESSAGE, # response_type
         32, # format
@@ -119,7 +119,7 @@ is($nodes->[0]->{window}, $M->{id}, 'M is left of S');
 is($nodes->[1]->{window}, $S->{id}, 'S is right of M');
 
 ###############################################################################
-# Given 'S' and 'M' on different workspaces and 'S' is urgent, when 'S' is 
+# Given 'S' and 'M' on different workspaces and 'S' is urgent, when 'S' is
 # moved to 'M', then the urgency flag is transferred to the target workspace.
 ###############################################################################
 
diff --git a/testcases/t/245-move-position-mouse.t b/testcases/t/245-move-position-mouse.t
index 12f890f2..01e2c30e 100644
--- a/testcases/t/245-move-position-mouse.t
+++ b/testcases/t/245-move-position-mouse.t
@@ -58,7 +58,7 @@ exit_gracefully($pid);
 
 ##########################################################################
 # Given a floating container and the cursor is in the left upper edge
-# of the output, when moving the container to the mouse, then the 
+# of the output, when moving the container to the mouse, then the
 # container is moved but adjusted to stay in-bounds.
 ##########################################################################
 
@@ -84,7 +84,7 @@ exit_gracefully($pid);
 
 ##########################################################################
 # Given a floating container and the cursor is in the left right lower
-# edge of the output, when moving the container to the mouse, then the 
+# edge of the output, when moving the container to the mouse, then the
 # container is moved but adjusted to stay in-bounds.
 ##########################################################################
 
diff --git a/testcases/t/253-multiple-net-wm-state-atoms.t b/testcases/t/253-multiple-net-wm-state-atoms.t
index 3790f92d..392beae1 100644
--- a/testcases/t/253-multiple-net-wm-state-atoms.t
+++ b/testcases/t/253-multiple-net-wm-state-atoms.t
@@ -21,15 +21,15 @@ use X11::XCB qw(:all);
 sub get_wm_state {
     sync_with_i3;
 
-    my ($con) = @_; 
+    my ($con) = @_;
     my $cookie = $x->get_property(
-        0,  
+        0,
         $con->{id},
         $x->atom(name => '_NET_WM_STATE')->id,
         GET_PROPERTY_TYPE_ANY,
-        0,  
+        0,
         4096
-    );  
+    );
 
     my $reply = $x->get_property_reply($cookie->{sequence});
     my $len = $reply->{length};
diff --git a/testcases/t/529-net-wm-desktop.t b/testcases/t/529-net-wm-desktop.t
index ae596203..f1da2980 100644
--- a/testcases/t/529-net-wm-desktop.t
+++ b/testcases/t/529-net-wm-desktop.t
@@ -31,15 +31,15 @@ use X11::XCB qw(:all);
 sub get_net_wm_desktop {
     sync_with_i3;
 
-    my ($con) = @_; 
+    my ($con) = @_;
     my $cookie = $x->get_property(
-        0,  
+        0,
         $con->{id},
         $x->atom(name => '_NET_WM_DESKTOP')->id,
         $x->atom(name => 'CARDINAL')->id,
-        0,  
+        0,
         1
-    );  
+    );
 
     my $reply = $x->get_property_reply($cookie->{sequence});
     return undef if $reply->{length} != 1;