diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2f76edec..cce5885f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -381,7 +381,7 @@ elseif(FORMAT_TEST)
 endif()
 
 function(auto_test target)
-  if(CHECK_FOUND)
+  if(CHECK_FOUND AND NOT ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" AND ARGV1 STREQUAL "MSVC_DONT_BUILD"))
     add_c_executable(auto_${target}_test auto_tests/${target}_test.c)
     target_link_modules(auto_${target}_test
       toxcore
@@ -390,8 +390,10 @@ function(auto_test target)
     if(BUILD_TOXAV)
       target_link_modules(auto_${target}_test toxav)
     endif()
-    add_test(NAME ${target} COMMAND auto_${target}_test)
-    set_tests_properties(${target} PROPERTIES TIMEOUT "${TEST_TIMEOUT_SECONDS}")
+    if(NOT ARGV1 STREQUAL "DONT_RUN")
+      add_test(NAME ${target} COMMAND auto_${target}_test)
+      set_tests_properties(${target} PROPERTIES TIMEOUT "${TEST_TIMEOUT_SECONDS}")
+    endif()
   endif()
 endfunction()
 
@@ -407,10 +409,10 @@ endif()
 
 auto_test(TCP)
 auto_test(conference)
-auto_test(crypto)
-auto_test(dht)
+auto_test(crypto                        MSVC_DONT_BUILD)
+auto_test(dht                           MSVC_DONT_BUILD)
 auto_test(encryptsave)
-auto_test(messenger)
+auto_test(messenger                     MSVC_DONT_BUILD)
 auto_test(network)
 auto_test(onion)
 auto_test(resource_leak)
@@ -424,8 +426,8 @@ auto_test(tox_strncasecmp)
 auto_test(version)
 # TODO(iphydf): These tests are broken. The code needs to be fixed, as the
 # tests themselves are correct.
-#auto_test(selfname_change_conference)
-#auto_test(self_conference_title_change)
+auto_test(selfname_change_conference    DONT_RUN)
+auto_test(self_conference_title_change  DONT_RUN)
 
 if(BUILD_TOXAV)
   auto_test(toxav_basic)
diff --git a/appveyor.yml b/appveyor.yml
index 4b4bfb20..66453ccf 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,15 +1,26 @@
+cache:
+- '%APPDATA%\downloads'
+
 install:
 # TODO(iphydf): Remove this when appveyor gets curl back, which it should have
 # according to https://www.appveyor.com/docs/how-to/download-file/.
 - choco install curl
 - refreshenv
-- mkdir libsodium && cd libsodium
-- curl https://download.libsodium.org/libsodium/releases/libsodium-1.0.11-msvc.zip -o libsodium.zip
-- unzip libsodium.zip
+- if not exist %APPDATA%\downloads mkdir %APPDATA%\downloads
+# libcheck
+- if not exist %APPDATA%\downloads\check.zip curl -L https://github.com/libcheck/check/archive/0.11.0.zip -o %APPDATA%\downloads\check.zip
+- unzip %APPDATA%\downloads\check.zip && cd check-0.11.0
+- if not exist "%PROGRAMFILES%\check\include\check.h" cmake . && msbuild INSTALL.vcxproj
 - cd ..
+# libsodium
+- mkdir libsodium && cd libsodium
+- if not exist %APPDATA%\downloads\libsodium.zip curl -L https://download.libsodium.org/libsodium/releases/libsodium-1.0.12-msvc.zip -o %APPDATA%\downloads\libsodium.zip
+- unzip %APPDATA%\downloads\libsodium.zip
+- cd ..
+# pthreads-win32
 - mkdir pthreads-win32 && cd pthreads-win32
-- curl ftp://sourceware.org/pub/pthreads-win32/pthreads-w32-2-9-1-release.zip -o pthreads.zip
-- unzip pthreads.zip
+- if not exist %APPDATA%\downloads\pthreads.zip curl -L ftp://sourceware.org/pub/pthreads-win32/pthreads-w32-2-9-1-release.zip -o %APPDATA%\downloads\pthreads.zip
+- unzip %APPDATA%\downloads\pthreads.zip
 - cd ..
 
 before_build:
@@ -18,6 +29,10 @@ before_build:
 build:
   project: INSTALL.vcxproj
 
+# TODO(iphydf): Tests all segfault on Windows at the moment.
+#test_script:
+#- ctest -C Debug
+
 branches:
   only:
   - master
diff --git a/auto_tests/Makefile.inc b/auto_tests/Makefile.inc
index 244737d9..536b08c5 100644
--- a/auto_tests/Makefile.inc
+++ b/auto_tests/Makefile.inc
@@ -123,4 +123,5 @@ tox_strncasecmp_test_CFLAGS = $(AUTOTEST_CFLAGS)
 tox_strncasecmp_test_LDADD = $(AUTOTEST_LDADD)
 
 
+EXTRA_DIST += $(top_srcdir)/auto_tests/check_compat.h
 EXTRA_DIST += $(top_srcdir)/auto_tests/helpers.h
diff --git a/auto_tests/TCP_test.c b/auto_tests/TCP_test.c
index 769ba5de..f8412832 100644
--- a/auto_tests/TCP_test.c
+++ b/auto_tests/TCP_test.c
@@ -4,7 +4,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/auto_tests/check_compat.h b/auto_tests/check_compat.h
new file mode 100644
index 00000000..e4fde89f
--- /dev/null
+++ b/auto_tests/check_compat.h
@@ -0,0 +1,8 @@
+#ifdef _MSC_VER
+#define pid_t int
+// #include <libcompat.h>
+#endif
+#include <check.h>
+#ifdef _MSC_VER
+#undef pid_t
+#endif
diff --git a/auto_tests/conference_test.c b/auto_tests/conference_test.c
index 33110441..e8d7e238 100644
--- a/auto_tests/conference_test.c
+++ b/auto_tests/conference_test.c
@@ -7,7 +7,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <inttypes.h>
 #include <stdlib.h>
 #include <time.h>
diff --git a/auto_tests/crypto_test.c b/auto_tests/crypto_test.c
index 952b0312..2fdfb0cd 100644
--- a/auto_tests/crypto_test.c
+++ b/auto_tests/crypto_test.c
@@ -2,9 +2,8 @@
 #include "config.h"
 #endif
 
-#include "../toxcore/net_crypto.h"
+#include "check_compat.h"
 
-#include <check.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -13,6 +12,8 @@
 
 #include "helpers.h"
 
+#include "../toxcore/net_crypto.h"
+
 static void rand_bytes(uint8_t *b, size_t blen)
 {
     size_t i;
diff --git a/auto_tests/dht_test.c b/auto_tests/dht_test.c
index 5533593f..c04b67e4 100644
--- a/auto_tests/dht_test.c
+++ b/auto_tests/dht_test.c
@@ -4,14 +4,16 @@
 #include "config.h"
 #endif
 
+#include "check_compat.h"
+
+#include <sys/param.h>
+#include <time.h>
+
 #include "helpers.h"
 
 #include "../toxcore/DHT.c"
 #include "../toxcore/tox.h"
 
-#include <sys/param.h>
-#include <time.h>
-
 
 // These tests currently fail.
 static bool enable_broken_tests = false;
diff --git a/auto_tests/encryptsave_test.c b/auto_tests/encryptsave_test.c
index 749767a0..dfe85710 100644
--- a/auto_tests/encryptsave_test.c
+++ b/auto_tests/encryptsave_test.c
@@ -2,7 +2,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/auto_tests/file_saving_test.c b/auto_tests/file_saving_test.c
index 8cff56e8..0d167b5a 100644
--- a/auto_tests/file_saving_test.c
+++ b/auto_tests/file_saving_test.c
@@ -22,6 +22,7 @@
  * You should have received a copy of the GNU General Public License
  * along with Tox.  If not, see <http://www.gnu.org/licenses/>.
  */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/auto_tests/helpers.h b/auto_tests/helpers.h
index e5860449..55cc1ca0 100644
--- a/auto_tests/helpers.h
+++ b/auto_tests/helpers.h
@@ -4,25 +4,25 @@
 #include "../toxcore/tox.h"
 
 #include <assert.h>
-#include <check.h>
 #include <stdio.h>
+#include <string.h>
 
-#if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
+#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)
 #include <windows.h>
 #define c_sleep(x) Sleep(x)
 #else
 #include <unistd.h>
-#define c_sleep(x) usleep(1000*(x))
+#define c_sleep(x) usleep(1000 * (x))
 #endif
 
 #define DEFTESTCASE(NAME)                   \
     TCase *tc_##NAME = tcase_create(#NAME); \
     tcase_add_test(tc_##NAME, test_##NAME); \
-    suite_add_tcase(s, tc_##NAME);
+    suite_add_tcase(s, tc_##NAME)
 
-#define DEFTESTCASE_SLOW(NAME, TIMEOUT) \
-    DEFTESTCASE(NAME) \
-    tcase_set_timeout(tc_##NAME, TIMEOUT);
+#define DEFTESTCASE_SLOW(NAME, TIMEOUT)     \
+    DEFTESTCASE(NAME);                      \
+    tcase_set_timeout(tc_##NAME, TIMEOUT)
 
 static const char *tox_log_level_name(TOX_LOG_LEVEL level)
 {
diff --git a/auto_tests/messenger_test.c b/auto_tests/messenger_test.c
index bd524014..614b1057 100644
--- a/auto_tests/messenger_test.c
+++ b/auto_tests/messenger_test.c
@@ -14,12 +14,13 @@
 #include "config.h"
 #endif
 
+#include "check_compat.h"
+
 #include "helpers.h"
 
 #include "../testing/misc_tools.c" // hex_string_to_bin
 #include "../toxcore/Messenger.h"
 
-#include <check.h>
 #include <stdint.h>
 #include <string.h>
 #include <sys/types.h>
diff --git a/auto_tests/monolith_test.c b/auto_tests/monolith_test.c
index d6f675a2..253d2bd3 100644
--- a/auto_tests/monolith_test.c
+++ b/auto_tests/monolith_test.c
@@ -1,12 +1,13 @@
 /* Auto Tests: One instance.
  */
 
+#define _DARWIN_C_SOURCE
+#define _XOPEN_SOURCE 600
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#define _DARWIN_C_SOURCE
-#define _XOPEN_SOURCE 600
 #include "../other/monolith.h"
 
 int main(int argc, char *argv[])
diff --git a/auto_tests/network_test.c b/auto_tests/network_test.c
index 9ae1ddcb..67090f74 100644
--- a/auto_tests/network_test.c
+++ b/auto_tests/network_test.c
@@ -2,7 +2,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <errno.h>
 #include <stdint.h>
 #include <stdlib.h>
diff --git a/auto_tests/onion_test.c b/auto_tests/onion_test.c
index c52bbb58..a0d4f4bc 100644
--- a/auto_tests/onion_test.c
+++ b/auto_tests/onion_test.c
@@ -4,7 +4,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/auto_tests/resource_leak_test.c b/auto_tests/resource_leak_test.c
index 3a87e245..5b25bc77 100644
--- a/auto_tests/resource_leak_test.c
+++ b/auto_tests/resource_leak_test.c
@@ -1,9 +1,9 @@
-#include "helpers.h"
-
 #if defined(__AIX__)
-#   define _XOPEN_SOURCE 1
+#define _XOPEN_SOURCE 1
 #endif
 
+#include "helpers.h"
+
 // See man 2 sbrk.
 #if _BSD_SOURCE || _SVID_SOURCE || \
   (_XOPEN_SOURCE >= 500 || \
diff --git a/auto_tests/self_conference_title_change_test.c b/auto_tests/self_conference_title_change_test.c
index f0896101..a91aa0b4 100644
--- a/auto_tests/self_conference_title_change_test.c
+++ b/auto_tests/self_conference_title_change_test.c
@@ -21,6 +21,7 @@
  *  along with Tox.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+#define _XOPEN_SOURCE 500
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -30,6 +31,8 @@
 #include "../toxcore/tox.h"
 #include "../toxencryptsave/toxencryptsave.h"
 
+#include "helpers.h"
+
 static const char *newtitle = "kitten over darknet";
 
 static void cbtitlechange(Tox *tox, uint32_t conference_number, uint32_t peer_number, const uint8_t *title,
@@ -44,7 +47,6 @@ static void cbtitlechange(Tox *tox, uint32_t conference_number, uint32_t peer_nu
 int main(void)
 {
     uint32_t conference_number;
-    struct timespec sleeptime;
     struct Tox_Options to;
     Tox *t;
     TOX_ERR_CONFERENCE_NEW conference_err;
@@ -62,11 +64,7 @@ int main(void)
     }
 
     tox_iterate(t, NULL);
-
-    sleeptime.tv_sec = 0;
-    sleeptime.tv_nsec = tox_iteration_interval(t) * 1E6;
-
-    nanosleep(&sleeptime, NULL);
+    c_sleep(tox_iteration_interval(t));
 
     if (!tox_conference_set_title(t, conference_number, (const uint8_t *)newtitle, strlen(newtitle), &title_err)) {
         tox_kill(t);
@@ -75,7 +73,7 @@ int main(void)
     }
 
     tox_iterate(t, NULL);
-    nanosleep(&sleeptime, NULL);
+    c_sleep(tox_iteration_interval(t));
     tox_iterate(t, NULL);
 
     fprintf(stderr, "error: title was not changed in callback. exiting.\n");
diff --git a/auto_tests/selfname_change_conference_test.c b/auto_tests/selfname_change_conference_test.c
index 340f7aa6..2536b10e 100644
--- a/auto_tests/selfname_change_conference_test.c
+++ b/auto_tests/selfname_change_conference_test.c
@@ -21,12 +21,15 @@
  *  along with Tox.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+#define _XOPEN_SOURCE 500
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
+#include "helpers.h"
+
 #include "../toxcore/tox.h"
 #include "../toxencryptsave/toxencryptsave.h"
 
@@ -55,7 +58,6 @@ static void cbconfmembers(Tox *tox, uint32_t conference_number, uint32_t peer_nu
 int main(void)
 {
     uint32_t conference_number;
-    struct timespec sleeptime;
     struct Tox_Options to;
     Tox *t;
     TOX_ERR_CONFERENCE_NEW conference_err;
@@ -73,11 +75,7 @@ int main(void)
     }
 
     tox_iterate(t, NULL);
-
-    sleeptime.tv_sec = 0;
-    sleeptime.tv_nsec = tox_iteration_interval(t) * 1E6;
-
-    nanosleep(&sleeptime, NULL);
+    c_sleep(tox_iteration_interval(t));
 
     if (!tox_self_set_name(t, (const uint8_t *)newname, strlen(newname), &name_err)) {
         tox_kill(t);
@@ -86,7 +84,7 @@ int main(void)
     }
 
     tox_iterate(t, NULL);
-    nanosleep(&sleeptime, NULL);
+    c_sleep(tox_iteration_interval(t));
     tox_iterate(t, NULL);
 
     fprintf(stderr, "error: name was not changed in callback. exiting.\n");
diff --git a/auto_tests/skeleton_test.c b/auto_tests/skeleton_test.c
index b8950921..48f95093 100644
--- a/auto_tests/skeleton_test.c
+++ b/auto_tests/skeleton_test.c
@@ -2,11 +2,9 @@
 #include "config.h"
 #endif
 
-#include <check.h>
-#include <stdint.h>
+#include "check_compat.h"
+
 #include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
 #include <time.h>
 
 #include "helpers.h"
diff --git a/auto_tests/tox_many_tcp_test.c b/auto_tests/tox_many_tcp_test.c
index 77c611d9..510109ee 100644
--- a/auto_tests/tox_many_tcp_test.c
+++ b/auto_tests/tox_many_tcp_test.c
@@ -7,7 +7,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
diff --git a/auto_tests/tox_many_test.c b/auto_tests/tox_many_test.c
index 1a1a715d..a34cfa8d 100644
--- a/auto_tests/tox_many_test.c
+++ b/auto_tests/tox_many_test.c
@@ -7,7 +7,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
diff --git a/auto_tests/tox_one_test.c b/auto_tests/tox_one_test.c
index ce698486..1b277d96 100644
--- a/auto_tests/tox_one_test.c
+++ b/auto_tests/tox_one_test.c
@@ -5,7 +5,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdlib.h>
 #include <time.h>
 
diff --git a/auto_tests/tox_strncasecmp_test.c b/auto_tests/tox_strncasecmp_test.c
index 0acc85fe..5e0edcbd 100644
--- a/auto_tests/tox_strncasecmp_test.c
+++ b/auto_tests/tox_strncasecmp_test.c
@@ -2,7 +2,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/auto_tests/tox_test.c b/auto_tests/tox_test.c
index f3557226..3613b9c4 100644
--- a/auto_tests/tox_test.c
+++ b/auto_tests/tox_test.c
@@ -16,7 +16,8 @@
 #include "config.h"
 #endif
 
-#include <check.h>
+#include "check_compat.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
diff --git a/auto_tests/toxav_basic_test.c b/auto_tests/toxav_basic_test.c
index 2885d8be..2b77da37 100644
--- a/auto_tests/toxav_basic_test.c
+++ b/auto_tests/toxav_basic_test.c
@@ -4,7 +4,7 @@
 #include "config.h"
 #endif
 
-#include "helpers.h"
+#include "check_compat.h"
 
 #include <stdint.h>
 #include <stdio.h>
@@ -21,6 +21,7 @@
 #include "../toxcore/tox.h"
 #include "../toxcore/util.h"
 
+#include "helpers.h"
 
 #define TEST_REGULAR_AV 1
 #define TEST_REGULAR_A 1
diff --git a/auto_tests/toxav_many_test.c b/auto_tests/toxav_many_test.c
index 83a7b313..5796905c 100644
--- a/auto_tests/toxav_many_test.c
+++ b/auto_tests/toxav_many_test.c
@@ -4,7 +4,7 @@
 #include "config.h"
 #endif
 
-#include "helpers.h"
+#include "check_compat.h"
 
 #include <stdint.h>
 #include <stdio.h>
@@ -21,6 +21,8 @@
 #include "../toxcore/tox.h"
 #include "../toxcore/util.h"
 
+#include "helpers.h"
+
 #if !defined(_WIN32) && !defined(__WIN32__) && !defined(WIN32)
 #include <pthread.h>
 #endif
diff --git a/cmake/Dependencies.cmake b/cmake/Dependencies.cmake
index 5ad332bd..b87922a9 100644
--- a/cmake/Dependencies.cmake
+++ b/cmake/Dependencies.cmake
@@ -35,36 +35,71 @@ pkg_use_module(SNDFILE              sndfile      )
 
 ###############################################################################
 #
-# :: For Windows and other systems lacking pkg-config.
+# :: For MSVC Windows builds.
+#
+# These require specific installation paths of dependencies:
+# - libsodium in libsodium/Win32/Release/v140/static
+# - pthreads in pthreads-win32/Pre-built.2
+# - check in %PROGRAMFILES%/check
 #
 ###############################################################################
 
-if(NOT LIBSODIUM_FOUND)
-  include_directories(libsodium/include)
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+  # libsodium
+  # ---------
   find_library(LIBSODIUM_LIBRARIES
-    NAMES
-      sodium
-      libsodium
+    NAMES sodium libsodium
     PATHS
-      libsodium/Win32/Release/v140/static
-      libsodium/x64/Release/v140/static
+      "libsodium/Win32/Release/v140/static"
+      "libsodium/x64/Release/v140/static"
   )
   if(LIBSODIUM_LIBRARIES)
+    include_directories("libsodium/include")
     set(LIBSODIUM_FOUND TRUE)
+    add_definitions(-DSODIUM_STATIC)
+    message("libsodium: ${LIBSODIUM_LIBRARIES}")
+  else()
+    message(FATAL_ERROR "libsodium libraries not found")
   endif()
-  add_definitions(-DSODIUM_STATIC)
-  message("libsodium: ${LIBSODIUM_LIBRARIES}")
-endif()
 
-if(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC") AND CMAKE_USE_WIN32_THREADS_INIT)
-  include_directories(pthreads-win32/Pre-built.2/include)
-  find_library(CMAKE_THREAD_LIBS_INIT
-    NAMES
-      pthreadVC2
-    PATHS
-      pthreads-win32/Pre-built.2/lib/x86
-      pthreads-win32/Pre-built.2/lib/x64
+  # check
+  # -----
+  #
+  # We look for the check and compat (containing clock_gettime and other POSIX
+  # functions not present on Windows) libraries in Program Files, since that is
+  # the default location where cmake installs its packages.
+  find_library(LIBCHECK_LIBRARIES
+    NAMES check libcheck
+    PATHS "$ENV{PROGRAMFILES}/check/lib"
   )
-  add_definitions(-DHAVE_STRUCT_TIMESPEC)
-  message("libpthreads: ${CMAKE_THREAD_LIBS_INIT}")
+  find_library(LIBCOMPAT_LIBRARIES
+    NAMES compat libcompat
+    PATHS "$ENV{PROGRAMFILES}/check/lib"
+  )
+  if(LIBCHECK_LIBRARIES AND LIBCOMPAT_LIBRARIES)
+    include_directories("$ENV{PROGRAMFILES}/check/include")
+    set(CHECK_FOUND TRUE)
+    set(CHECK_LIBRARIES ${LIBCHECK_LIBRARIES} ${LIBCOMPAT_LIBRARIES})
+    message("check: ${CHECK_LIBRARIES}")
+  else()
+    message(FATAL_ERROR "check libraries not found")
+  endif()
+
+  # pthreads
+  # --------
+  if(CMAKE_USE_WIN32_THREADS_INIT)
+    find_library(CMAKE_THREAD_LIBS_INIT
+      NAMES pthreadVC2
+      PATHS
+        "pthreads-win32/Pre-built.2/lib/x86"
+        "pthreads-win32/Pre-built.2/lib/x64"
+    )
+    if(CMAKE_THREAD_LIBS_INIT)
+      include_directories("pthreads-win32/Pre-built.2/include")
+      add_definitions(-DHAVE_STRUCT_TIMESPEC)
+      message("libpthreads: ${CMAKE_THREAD_LIBS_INIT}")
+    else()
+      message(FATAL_ERROR "libpthreads libraries not found")
+    endif()
+  endif()
 endif()
diff --git a/testing/misc_tools.c b/testing/misc_tools.c
index f6e76e46..a3a89c2f 100644
--- a/testing/misc_tools.c
+++ b/testing/misc_tools.c
@@ -32,6 +32,7 @@
 #include <string.h>
 
 //Sleep function (x = milliseconds)
+#ifndef c_sleep
 #if defined(_WIN32) || defined(__WIN32__) || defined (WIN32)
 #include <windows.h>
 #define c_sleep(x) Sleep(x)
@@ -39,6 +40,7 @@
 #include <unistd.h>
 #define c_sleep(x) usleep(1000*(x))
 #endif
+#endif
 
 // You are responsible for freeing the return value!
 uint8_t *hex_string_to_bin(const char *hex_string)