diff --git a/boards/sim/sim/sim/configs/citest/defconfig b/boards/sim/sim/sim/configs/citest/defconfig
index 6d59280f63..8d38d4171c 100644
--- a/boards/sim/sim/sim/configs/citest/defconfig
+++ b/boards/sim/sim/sim/configs/citest/defconfig
@@ -81,6 +81,7 @@ CONFIG_SYSTEM_DUMPSTACK=y
 CONFIG_SYSTEM_NSH=y
 CONFIG_SYSTEM_POPEN=y
 CONFIG_TESTING_CXXTEST=y
+CONFIG_TESTING_FMEMOPEN_TEST=y
 CONFIG_TESTING_FOPENCOOKIE_TEST=y
 CONFIG_TESTING_FSTEST=y
 CONFIG_TESTING_FSTEST_MOUNTPT="/tmp"
diff --git a/tools/ci/testrun/script/test_os/test_os.py b/tools/ci/testrun/script/test_os/test_os.py
index 030872c063..ef026d2274 100644
--- a/tools/ci/testrun/script/test_os/test_os.py
+++ b/tools/ci/testrun/script/test_os/test_os.py
@@ -39,11 +39,13 @@ def test_getprime(p):
     assert ret == 0
 
 
-def test_fopencookie(p):
+def test_stdio(p):
     if p.board in do_not_support:
         pytest.skip("unsupported at {}".format(p.board))
     ret = p.sendCommand("fopencookie_test", "fopencokie tests were succesfull.")
     assert ret == 0
+    ret = p.sendCommand("fmemopen_test", "FAILED: 0")
+    assert ret == 0
 
 
 @pytest.mark.run(order=-2)