diff --git a/dist/pythonlibs/testrunner/__init__.py b/dist/pythonlibs/testrunner/__init__.py
index 3a372e5136..31fa260eb4 100755
--- a/dist/pythonlibs/testrunner/__init__.py
+++ b/dist/pythonlibs/testrunner/__init__.py
@@ -14,6 +14,7 @@ import pexpect
 
 from .spawn import find_exc_origin, setup_child, teardown_child
 from .unittest import PexpectTestCase   # noqa, F401 expose to users
+from .utils import test_utils_interactive_sync # noqa, F401 expose to users
 
 # Timeout for tests can be changed by setting RIOT_TEST_TIMEOUT to the desired
 # value in the environment variables
diff --git a/dist/pythonlibs/testrunner/utils.py b/dist/pythonlibs/testrunner/utils.py
new file mode 100644
index 0000000000..faee374235
--- /dev/null
+++ b/dist/pythonlibs/testrunner/utils.py
@@ -0,0 +1,27 @@
+# Copyright (C) 2019 Freie Universität Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+"""Utility functions for writing tests."""
+
+import pexpect
+
+
+def test_utils_interactive_sync(child, retries=5, delay=1):
+    """Synchronisation for 'test_utils_interactive_sync' function.
+
+    Interacts through input to wait for node being ready.
+    """
+    for _ in range(0, retries):
+        child.sendline('r')
+        ret = child.expect_exact(['READY', pexpect.TIMEOUT], timeout=delay)
+        if ret == 0:
+            break
+    else:
+        # Last call to make it fail her,
+        child.expect_exact('READY', timeout=0)
+
+    child.sendline('s')
+    child.expect_exact('START')
diff --git a/sys/Makefile b/sys/Makefile
index 058697f249..1926dabe36 100644
--- a/sys/Makefile
+++ b/sys/Makefile
@@ -25,6 +25,9 @@ endif
 ifneq (,$(filter shell_commands,$(USEMODULE)))
   DIRS += shell/commands
 endif
+ifneq (,$(filter test_utils_interactive_sync,$(USEMODULE)))
+  DIRS += test_utils/interactive_sync
+endif
 ifneq (,$(filter net_help,$(USEMODULE)))
   DIRS += net/crosslayer/net_help
 endif
diff --git a/sys/Makefile.dep b/sys/Makefile.dep
index f9afc587e3..dcddeac2bc 100644
--- a/sys/Makefile.dep
+++ b/sys/Makefile.dep
@@ -9,3 +9,5 @@ endif
 ifneq (,$(filter prng_fortuna,$(USEMODULE)))
   CFLAGS += -DCRYPTO_AES
 endif
+
+include $(RIOTBASE)/sys/test_utils/Makefile.dep
diff --git a/sys/include/test_utils/interactive_sync.h b/sys/include/test_utils/interactive_sync.h
new file mode 100644
index 0000000000..b27a571f2d
--- /dev/null
+++ b/sys/include/test_utils/interactive_sync.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    test_utils_interactive_sync Test interactive synchronization
+ * @ingroup     sys
+ * @brief       Utility function for synchronizing before a test
+ *
+ * @{
+ * @file
+ * @brief       Synchronization for normally non interactive tests
+ *
+ * @author      Gaëtan Harter <gaetan.harter@fu-berlin.de>
+ */
+
+#ifndef TEST_UTILS_INTERACTIVE_SYNC_H
+#define TEST_UTILS_INTERACTIVE_SYNC_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Wait for the tester to start test
+ *
+ * @details Wait for a 's' character to return
+ *
+ */
+void test_utils_interactive_sync(void);
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* TEST_UTILS_INTERACTIVE_SYNC_H */
+/** @} */
diff --git a/sys/test_utils/Makefile.dep b/sys/test_utils/Makefile.dep
new file mode 100644
index 0000000000..4bafa543b8
--- /dev/null
+++ b/sys/test_utils/Makefile.dep
@@ -0,0 +1,3 @@
+ifneq (,$(filter test_utils_interactive_sync,$(USEMODULE)))
+  USEMODULE += stdin
+endif
diff --git a/sys/test_utils/interactive_sync/Makefile b/sys/test_utils/interactive_sync/Makefile
new file mode 100644
index 0000000000..e22cec26b0
--- /dev/null
+++ b/sys/test_utils/interactive_sync/Makefile
@@ -0,0 +1,3 @@
+MODULE = test_utils_interactive_sync
+
+include $(RIOTBASE)/Makefile.base
diff --git a/sys/test_utils/interactive_sync/interactive_sync.c b/sys/test_utils/interactive_sync/interactive_sync.c
new file mode 100644
index 0000000000..6dba6ed425
--- /dev/null
+++ b/sys/test_utils/interactive_sync/interactive_sync.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include "test_utils/interactive_sync.h"
+
+void test_utils_interactive_sync(void)
+{
+    char c = '\0'; /* Print help on first loop */
+    do {
+        if (c == 'r') {
+            /* This one should have a different case than the help message
+             * otherwise we match it when using 'expect' */
+            puts("READY");
+        }
+        else if (c != '\n' && c != '\r') {
+            puts("Help: Press s to start test, r to print it is ready");
+        }
+        c = getchar();
+    } while (c != 's');
+
+    puts("START");
+}
diff --git a/tests/cond_order/Makefile b/tests/cond_order/Makefile
index 8795a8226e..f138bec203 100644
--- a/tests/cond_order/Makefile
+++ b/tests/cond_order/Makefile
@@ -7,4 +7,6 @@ BOARD_INSUFFICIENT_MEMORY := arduino-duemilanove arduino-leonardo arduino-nano \
                              nucleo-l031k6 nucleo-l053 nucleo-l053r8 \
                              stm32f0discovery stm32l0538-disco
 
+USEMODULE += test_utils_interactive_sync
+
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/cond_order/main.c b/tests/cond_order/main.c
index 249c776af9..e0b0f8bf7f 100644
--- a/tests/cond_order/main.c
+++ b/tests/cond_order/main.c
@@ -24,6 +24,7 @@
 #include "cond.h"
 #include "mutex.h"
 #include "thread.h"
+#include "test_utils/interactive_sync.h"
 
 #define THREAD_NUMOF            (5U)
 #define THREAD_FIRSTGROUP_NUMOF (3U)
@@ -62,6 +63,8 @@ int main(void)
     puts("Condition variable order test");
     puts("Please refer to the README.md for more information\n");
 
+    test_utils_interactive_sync();
+
     mutex_init(&testlock);
     cond_init(&testcond);
 
diff --git a/tests/cond_order/tests/01-run.py b/tests/cond_order/tests/01-run.py
index 106a9cf9f2..4d7ccd315a 100755
--- a/tests/cond_order/tests/01-run.py
+++ b/tests/cond_order/tests/01-run.py
@@ -10,6 +10,8 @@
 import os
 import sys
 
+from testrunner import test_utils_interactive_sync
+
 thread_prio = {
         3:  6,
         4:  4,
@@ -21,6 +23,8 @@ first_group_size = 3
 
 
 def testfunc(child):
+    test_utils_interactive_sync(child)
+
     for k in thread_prio.keys():
         child.expect(u"T%i \(prio %i\): waiting on condition variable now" % (k, thread_prio[k]))
 
diff --git a/tests/libfixmath/Makefile b/tests/libfixmath/Makefile
index ce035be05c..4fa74dcc92 100644
--- a/tests/libfixmath/Makefile
+++ b/tests/libfixmath/Makefile
@@ -2,7 +2,7 @@ include ../Makefile.tests_common
 
 USEPKG += libfixmath
 USEMODULE += libfixmath
-USEMODULE += xtimer
+USEMODULE += test_utils_interactive_sync
 
 TEST_ON_CI_WHITELIST += all
 
diff --git a/tests/libfixmath/main.c b/tests/libfixmath/main.c
index bf775239a4..48094637e1 100644
--- a/tests/libfixmath/main.c
+++ b/tests/libfixmath/main.c
@@ -30,8 +30,9 @@
 
 #include <stdio.h>
 
-#include "xtimer.h"
+#include "kernel_defines.h"
 #include "fix16.h"
+#include "test_utils/interactive_sync.h"
 
 #ifndef M_PI
 #   define M_PI 3.14159265359
@@ -185,8 +186,9 @@ static void unary_ops(void)
 
 int main(void)
 {
-    /* Delay output to prevent flooding of buffer */
-    xtimer_sleep(1);
+    /* Sync to prevent flooding of buffer */
+    test_utils_interactive_sync();
+
     puts("Unary.");
     unary_ops();
 
diff --git a/tests/libfixmath/tests/01-run.py b/tests/libfixmath/tests/01-run.py
index 29213751f7..21e42d95fa 100755
--- a/tests/libfixmath/tests/01-run.py
+++ b/tests/libfixmath/tests/01-run.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 
 import sys
-from testrunner import run
+from testrunner import run, test_utils_interactive_sync
 
 
 def expect_unary(child):
@@ -31,6 +31,7 @@ def expect_binary(child):
 
 
 def testfunc(child):
+    test_utils_interactive_sync(child)
     child.expect_exact('Unary.')
     expect_unary(child)
     child.expect_exact('Binary.')
diff --git a/tests/posix_time/Makefile b/tests/posix_time/Makefile
index d1a1ee9bb8..80171ab760 100644
--- a/tests/posix_time/Makefile
+++ b/tests/posix_time/Makefile
@@ -2,8 +2,7 @@ include ../Makefile.tests_common
 
 USEMODULE += posix_time
 
-# This application uses getchar and thus expects input from stdio
-USEMODULE += stdin
+USEMODULE += test_utils_interactive_sync
 
 TEST_ON_CI_WHITELIST += all
 
diff --git a/tests/posix_time/main.c b/tests/posix_time/main.c
index e79fbced2b..670838ca14 100644
--- a/tests/posix_time/main.c
+++ b/tests/posix_time/main.c
@@ -26,11 +26,11 @@
 
 #include <stdio.h>
 #include <unistd.h>
+#include "test_utils/interactive_sync.h"
 
 int main(void)
 {
-    puts("Please hit any key and then ENTER to continue");
-    getchar();
+    test_utils_interactive_sync();
     puts("5 x usleep(i++ * 500000)");
     for (unsigned i = 0; i < 5; i++) {
         useconds_t us = i * 500000u;
diff --git a/tests/posix_time/tests/01-run.py b/tests/posix_time/tests/01-run.py
index 2f4dab0d66..8a2d57433a 100755
--- a/tests/posix_time/tests/01-run.py
+++ b/tests/posix_time/tests/01-run.py
@@ -10,7 +10,7 @@
 
 import sys
 import time
-from testrunner import run
+from testrunner import run, test_utils_interactive_sync
 
 US_PER_SEC = 1000000
 EXTERNAL_JITTER = 0.15
@@ -22,8 +22,7 @@ class InvalidTimeout(Exception):
 
 def testfunc(child):
     try:
-        child.expect_exact("Please hit any key and then ENTER to continue")
-        child.sendline("a")
+        test_utils_interactive_sync(child)
         start_test = time.time()
         child.expect_exact("5 x usleep(i++ * 500000)")
         for i in range(5):
diff --git a/tests/xtimer_usleep/Makefile b/tests/xtimer_usleep/Makefile
index 48cf81df4e..db3f153186 100644
--- a/tests/xtimer_usleep/Makefile
+++ b/tests/xtimer_usleep/Makefile
@@ -6,8 +6,7 @@ TEST_ON_CI_WHITELIST += all
 # This test randomly fails on `native` so disable it from CI
 TEST_ON_CI_BLACKLIST += native
 
-# This application uses getchar and thus expects input from stdio
-USEMODULE += stdin
+USEMODULE += test_utils_interactive_sync
 
 # Port and pin configuration for probing with oscilloscope
 # Port number should be found in port enum e.g in cpu/include/periph_cpu.h
diff --git a/tests/xtimer_usleep/main.c b/tests/xtimer_usleep/main.c
index 12949b7fa5..f54d5c450e 100644
--- a/tests/xtimer_usleep/main.c
+++ b/tests/xtimer_usleep/main.c
@@ -27,6 +27,7 @@
 
 #include "xtimer.h"
 #include "timex.h"
+#include "test_utils/interactive_sync.h"
 
 #define RUNS                (5U)
 #define SLEEP_TIMES_NUMOF   ARRAY_SIZE(sleep_times)
@@ -61,8 +62,7 @@ int main(void)
 
     printf("Running test %u times with %u distinct sleep times\n", RUNS,
            (unsigned)SLEEP_TIMES_NUMOF);
-    puts("Please hit any key and then ENTER to continue");
-    getchar();
+    test_utils_interactive_sync();
     start_test = xtimer_now_usec();
     for (unsigned m = 0; m < RUNS; m++) {
         for (unsigned n = 0;
diff --git a/tests/xtimer_usleep/tests/01-run.py b/tests/xtimer_usleep/tests/01-run.py
index 3766be750a..bcf0927baf 100755
--- a/tests/xtimer_usleep/tests/01-run.py
+++ b/tests/xtimer_usleep/tests/01-run.py
@@ -11,7 +11,7 @@
 
 import sys
 import time
-from testrunner import run
+from testrunner import run, test_utils_interactive_sync
 
 
 US_PER_SEC = 1000000
@@ -28,8 +28,7 @@ def testfunc(child):
     RUNS = int(child.match.group(1))
     SLEEP_TIMES_NUMOF = int(child.match.group(2))
     try:
-        child.expect_exact(u"Please hit any key and then ENTER to continue")
-        child.sendline(u"a")
+        test_utils_interactive_sync(child)
         start_test = time.time()
         for m in range(RUNS):
             for n in range(SLEEP_TIMES_NUMOF):