diff --git a/testcases/t/65-for_window.t b/testcases/t/65-for_window.t
index 26ccb7cf..f156f11b 100644
--- a/testcases/t/65-for_window.t
+++ b/testcases/t/65-for_window.t
@@ -6,15 +6,9 @@
 use X11::XCB qw(:all);
 use X11::XCB::Connection;
 use i3test;
-use Cwd qw(abs_path);
-use Proc::Background;
-use File::Temp qw(tempfile tempdir);
 
 my $x = X11::XCB::Connection->new;
 
-# assuming we are run by complete-run.pl
-my $i3_path = abs_path("../i3");
-
 ##############################################################
 # 1: test the following directive:
 #    for_window [class="borderless"] border none
@@ -23,22 +17,14 @@ my $i3_path = abs_path("../i3");
 # "borderless" (should get no border)
 ##############################################################
 
-my $socketpath = File::Temp::tempnam('/tmp', 'i3-test-socket-');
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="borderless"] border none
+for_window [title="special borderless title"] border none
+EOT
 
-my ($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|for_window [class="borderless"] border none|;
-close($fh);
-
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
+my $process = launch_with_config($config);
 
 my $tmp = fresh_workspace;
 
@@ -112,21 +98,14 @@ exit_gracefully($process->pid);
 # only once
 ##############################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|for_window [class="borderless"] border none|;
-say $fh q|for_window [title="special borderless title"] border none|;
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="borderless"] border none
+for_window [title="special borderless title"] border none
+EOT
 
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
@@ -176,22 +155,16 @@ exit_gracefully($process->pid);
 # 3: match on the title, set border style *and* a mark
 ##############################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|for_window [class="borderless"] border none|;
-say $fh q|for_window [title="special borderless title"] border none|;
-say $fh q|for_window [title="special mark title"] border none, mark bleh|;
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="borderless" title="usethis"] border none
+for_window [class="borderless"] border none
+for_window [title="special borderless title"] border none
+for_window [title="special mark title"] border none, mark bleh
+EOT
 
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
@@ -228,20 +201,13 @@ exit_gracefully($process->pid);
 # 4: multiple criteria for the for_window command
 ##############################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|for_window [class="borderless" title="usethis"] border none|;
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="borderless" title="usethis"] border none
+EOT
 
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/tmp/a 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
diff --git a/testcases/t/66-assign.t b/testcases/t/66-assign.t
index 8e701277..a4a7bb0f 100644
--- a/testcases/t/66-assign.t
+++ b/testcases/t/66-assign.t
@@ -5,18 +5,12 @@
 # Tests if assignments work
 #
 use i3test;
-use Cwd qw(abs_path);
-use Proc::Background;
-use File::Temp qw(tempfile tempdir);
 use X11::XCB qw(:all);
 use X11::XCB::Connection;
 use v5.10;
 
 my $x = X11::XCB::Connection->new;
 
-# assuming we are run by complete-run.pl
-my $i3_path = abs_path("../i3");
-
 # TODO: move to X11::XCB
 sub set_wm_class {
     my ($id, $class, $instance) = @_;
@@ -41,23 +35,12 @@ sub set_wm_class {
 # start a window and see that it does not get assigned with an empty config
 #####################################################################
 
-my $socketpath = File::Temp::tempnam('/tmp', 'i3-test-socket-');
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+EOT
 
-my ($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-close($fh);
-
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+my $process = launch_with_config($config);
 
 my $tmp = fresh_workspace;
 
@@ -88,22 +71,13 @@ sleep 0.25;
 # workspace
 #####################################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|assign "special" → targetws|;
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+assign "special" → targetws
+EOT
 
-diag("Starting i3");
-$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-$process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
@@ -137,15 +111,7 @@ sleep 0.25;
 # already, next to the existing node.
 #####################################################################
 
-diag("Starting i3");
-$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-$process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+$process = launch_with_config($config);
 
 # initialize the target workspace, then go to a fresh one
 ok(!("targetws" ~~ @{get_workspace_names()}), 'targetws does not exist yet');
@@ -180,22 +146,13 @@ exit_gracefully($process->pid);
 # already, next to the existing node.
 #####################################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh q|assign "special" → ~|;
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+assign "special" → ~
+EOT
 
-diag("Starting i3");
-$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-$process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
diff --git a/testcases/t/67-workspace_layout.t b/testcases/t/67-workspace_layout.t
index cfe8bf64..2b9f6e56 100644
--- a/testcases/t/67-workspace_layout.t
+++ b/testcases/t/67-workspace_layout.t
@@ -6,39 +6,22 @@
 #
 
 use i3test;
-use Cwd qw(abs_path);
-use Proc::Background;
-use File::Temp qw(tempfile tempdir);
 use X11::XCB qw(:all);
 use X11::XCB::Connection;
 
 my $x = X11::XCB::Connection->new;
 
-# assuming we are run by complete-run.pl
-my $i3_path = abs_path("../i3");
-
 #####################################################################
 # 1: check that with an empty config, cons are place next to each
 # other and no split containers are created
 #####################################################################
 
-my $socketpath = File::Temp::tempnam('/tmp', 'i3-test-socket-');
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+EOT
 
-my ($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-close($fh);
-
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+my $process = launch_with_config($config);
 
 my $tmp = fresh_workspace;
 
@@ -59,22 +42,13 @@ exit_gracefully($process->pid);
 # they end up in a stacked con
 #####################################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh "workspace_layout stacked";
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+workspace_layout stacked
+EOT
 
-diag("Starting i3");
-$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-$process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
diff --git a/testcases/t/70-force_focus_wrapping.t b/testcases/t/70-force_focus_wrapping.t
index 020a3603..f2dfc18e 100644
--- a/testcases/t/70-force_focus_wrapping.t
+++ b/testcases/t/70-force_focus_wrapping.t
@@ -5,37 +5,21 @@
 # Tests if the 'force_focus_wrapping' config directive works correctly.
 #
 use i3test;
-use Cwd qw(abs_path);
-use Proc::Background;
-use File::Temp qw(tempfile tempdir);
 use X11::XCB qw(:all);
 use X11::XCB::Connection;
 
 my $x = X11::XCB::Connection->new;
 
-# assuming we are run by complete-run.pl
-my $i3_path = abs_path("../i3");
-my $socketpath = File::Temp::tempnam('/tmp', 'i3-test-socket-');
-
 #####################################################################
 # 1: test the wrapping behaviour without force_focus_wrapping
 #####################################################################
 
-my ($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-close($fh);
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+EOT
 
-diag("Starting i3");
-my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-my $process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+my $process = launch_with_config($config);
 
 my $tmp = fresh_workspace;
 
@@ -70,22 +54,13 @@ exit_gracefully($process->pid);
 # 2: test the wrapping behaviour with force_focus_wrapping
 #####################################################################
 
-($fh, $tmpfile) = tempfile();
-say $fh "# i3 config file (v4)";
-say $fh "font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1";
-say $fh "ipc-socket $socketpath";
-say $fh "force_focus_wrapping true";
-close($fh);
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+force_focus_wrapping true
+EOT
 
-diag("Starting i3");
-$i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
-$process = Proc::Background->new($i3cmd);
-sleep 1;
-
-# force update of the cached socket path in lib/i3test
-get_socket_path(0);
-
-diag("pid = " . $process->pid);
+$process = launch_with_config($config);
 
 $tmp = fresh_workspace;
 
diff --git a/testcases/t/lib/i3test.pm b/testcases/t/lib/i3test.pm
index bd40f565..054bb2ae 100644
--- a/testcases/t/lib/i3test.pm
+++ b/testcases/t/lib/i3test.pm
@@ -1,7 +1,7 @@
 package i3test;
 # vim:ts=4:sw=4:expandtab
 
-use File::Temp qw(tmpnam);
+use File::Temp qw(tmpnam tempfile tempdir);
 use Test::Builder;
 use X11::XCB::Rect;
 use X11::XCB::Window;
@@ -11,13 +11,17 @@ use List::Util qw(first);
 use List::MoreUtils qw(lastval);
 use Time::HiRes qw(sleep);
 use Try::Tiny;
+use Cwd qw(abs_path);
+use Proc::Background;
+
 use v5.10;
 
 use Exporter ();
-our @EXPORT = qw(get_workspace_names get_unused_workspace fresh_workspace get_ws_content get_ws get_focused open_empty_con open_standard_window get_dock_clients cmd does_i3_live exit_gracefully workspace_exists focused_ws get_socket_path);
+our @EXPORT = qw(get_workspace_names get_unused_workspace fresh_workspace get_ws_content get_ws get_focused open_empty_con open_standard_window get_dock_clients cmd does_i3_live exit_gracefully workspace_exists focused_ws get_socket_path launch_with_config);
 
 my $tester = Test::Builder->new();
 my $_cached_socket_path = undef;
+my $tmp_socket_path = undef;
 
 BEGIN {
     my $window_count = 0;
@@ -229,4 +233,33 @@ sub get_socket_path {
     return $socketpath;
 }
 
+#
+# launches a new i3 process with the given string as configuration file.
+# useful for tests which test specific config file directives.
+#
+# be sure to use !NO_I3_INSTANCE! somewhere in the file to signal
+# complete-run.pl that it should not create an instance of i3
+#
+sub launch_with_config {
+    my ($config) = @_;
+
+    if (!defined($tmp_socket_path)) {
+        $tmp_socket_path = File::Temp::tempnam('/tmp', 'i3-test-socket-');
+    }
+
+    my ($fh, $tmpfile) = tempfile('i3-test-config-XXXXX', UNLINK => 1);
+    say $fh $config;
+    say $fh "ipc-socket $tmp_socket_path";
+    close($fh);
+
+    my $i3cmd = "exec " . abs_path("../i3") . " -V -d all --disable-signalhandler -c $tmpfile >/dev/null 2>/dev/null";
+    my $process = Proc::Background->new($i3cmd);
+    sleep 1;
+
+    # force update of the cached socket path in lib/i3test
+    get_socket_path(0);
+
+    return $process;
+}
+
 1