diff --git a/tests/posix_time/Makefile b/tests/posix_time/Makefile
index 555036d53c..d1a1ee9bb8 100644
--- a/tests/posix_time/Makefile
+++ b/tests/posix_time/Makefile
@@ -2,6 +2,9 @@ include ../Makefile.tests_common
 
 USEMODULE += posix_time
 
+# This application uses getchar and thus expects input from stdio
+USEMODULE += stdin
+
 TEST_ON_CI_WHITELIST += all
 
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/xtimer_usleep/Makefile b/tests/xtimer_usleep/Makefile
index a51966755e..1af1bdee92 100644
--- a/tests/xtimer_usleep/Makefile
+++ b/tests/xtimer_usleep/Makefile
@@ -5,6 +5,9 @@ USEMODULE += xtimer
 # This test randomly fails on `native` so disable it from CI
 TEST_ON_CI_WHITELIST += samr21-xpro
 
+# This application uses getchar and thus expects input from stdio
+USEMODULE += stdin
+
 # Port and pin configuration for probing with oscilloscope
 # Port number should be found in port enum e.g in cpu/include/periph_cpu.h
 #FEATURES_REQUIRED += periph_gpio