diff --git a/src/kernel/Jmk b/src/kernel/Jmk
index 0ae3053..ddbc343 100644
--- a/src/kernel/Jmk
+++ b/src/kernel/Jmk
@@ -16,7 +16,10 @@
 # AHCI not yet implemented
 # depends(ahci, dri/ahci, ahci.a)
 
-CFLAGS += -I $(ROOT)/include/kernel
+TEST ?=
+test_defines = $(TEST:%=-DTEST_%)
+
+CFLAGS += -I $(ROOT)/include/kernel $(test_defines)
 
 LDFLAGS += -Tlink.ld -melf_i386
 ASMFLAGS += -felf -Fdwarf