diff --git a/testing/makefiles/libcommon.mk b/testing/makefiles/libcommon.mk
index 5da205be..3dc476a4 100644
--- a/testing/makefiles/libcommon.mk
+++ b/testing/makefiles/libcommon.mk
@@ -1,8 +1,9 @@
-top_dir		:= $(abspath $(dir $(lastword ${MAKEFILE_LIST}))../..)
-build_dir := ${top_dir}/_build
+mkfile_dir      := $(dir $(lastword ${MAKEFILE_LIST}))
+top_dir         := $(abspath $(mkfile_dir)../..)
 
+include $(mkfile_dir)/shared.mk
 
-bundle_path = ${ARDUINO_DIRECTORIES_USER}/hardware/keyboardio/avr/libraries
+build_dir := ${top_dir}/_build
 
 LIB_DIR := ${build_dir}/lib
 OBJ_DIR := ${build_dir}/obj
@@ -31,24 +32,7 @@ ${LIB_DIR}/${LIB_FILE}: ${OBJ_FILES}
 ${OBJ_DIR}/%.o: ${top_dir}/testing/%.cpp ${H_FILES}
 	$(info compile $@)
 	@install -d "${OBJ_DIR}"
-	$(COMPILER_WRAPPER) g++ -o "$@" -c \
-	  -std=c++14 \
-		-I${top_dir} \
-		-I${top_dir}/src \
-		-I${bundle_path}/../../virtual/cores/arduino \
-		-I${bundle_path}/KeyboardioHID/src \
-		-I${top_dir}/testing/googletest/googlemock/include \
-		-I${top_dir}/testing/googletest/googletest/include \
-		-DARDUINO=10607 \
-		-DARDUINO_ARCH_VIRTUAL \
-		-DARDUINO_AVR_MODEL01 \
-		'-DKALEIDOSCOPE_HARDWARE_H="Kaleidoscope-Hardware-Model01.h"' \
-		-DKALEIDOSCOPE_VIRTUAL_BUILD=1 \
-		-DKEYBOARDIOHID_BUILD_WITHOUT_HID=1 \
-		-DUSBCON=dummy \
-		-DARDUINO_ARCH_AVR=1 \
-		'-DUSB_PRODUCT="Model 01"' \
-		$<
+	$(COMPILER_WRAPPER) g++ -o "$@" -c -std=c++14 ${shared_includes} ${shared_defines} $<
 
 clean:
 	rm -rf -- "${build_dir}"
diff --git a/testing/makefiles/shared.mk b/testing/makefiles/shared.mk
new file mode 100644
index 00000000..9c4b2e32
--- /dev/null
+++ b/testing/makefiles/shared.mk
@@ -0,0 +1,21 @@
+arduino_platform_path := ${ARDUINO_DIRECTORIES_USER}/hardware/keyboardio/virtual/
+
+shared_defines := \
+                -DARDUINO=10607 \
+                -DARDUINO_ARCH_VIRTUAL \
+                -DKALEIDOSCOPE_VIRTUAL_BUILD=1 \
+                -DKEYBOARDIOHID_BUILD_WITHOUT_HID=1 \
+                -DUSBCON=dummy \
+                -DARDUINO_ARCH_AVR=1 \
+                -DARDUINO_AVR_MODEL01 \
+                '-DKALEIDOSCOPE_HARDWARE_H="Kaleidoscope-Hardware-Model01.h"' \
+                '-DUSB_PRODUCT="Model 01"'
+
+shared_includes := \
+		-I${top_dir} \
+		-I${top_dir}/src \
+		-I${arduino_platform_path}/cores/arduino \
+		-I${arduino_platform_path}/libraries/KeyboardioHID/src \
+		-I${top_dir}/testing/googletest/googlemock/include \
+		-I${top_dir}/testing/googletest/googletest/include \
+
diff --git a/testing/makefiles/testcase.mk b/testing/makefiles/testcase.mk
index 85b2632a..9e9111d5 100644
--- a/testing/makefiles/testcase.mk
+++ b/testing/makefiles/testcase.mk
@@ -1,9 +1,10 @@
-top_dir         := $(abspath $(dir $(lastword ${MAKEFILE_LIST}))../..)
+mkfile_dir 	:= $(dir $(lastword ${MAKEFILE_LIST}))
+top_dir         := $(abspath $(mkfile_dir)../..)
 
+include $(mkfile_dir)/shared.mk
 
 build_dir := ${top_dir}/_build/${testcase}
 
-
 LIB_DIR := ${build_dir}/lib
 OBJ_DIR := ${build_dir}/obj
 BIN_DIR	:= ${build_dir}/bin
@@ -40,8 +41,6 @@ endif
 
 TEST_OBJS=$(patsubst $(SRC_DIR)/%.cpp,${OBJ_DIR}/%.o,$(TEST_FILES))
 
-bundle_path = ${ARDUINO_DIRECTORIES_USER}/hardware/keyboardio/avr/libraries
-
 build: ${BIN_DIR}/${BIN_FILE} compile-sketch
 
 all: run
@@ -93,24 +92,8 @@ endif
 ${OBJ_DIR}/%.o: ${SRC_DIR}/%.cpp
 	@echo "compile $@"
 	install -d "${OBJ_DIR}"
-	$(COMPILER_WRAPPER) $(call _arduino_prop,compiler.cpp.cmd) -o "$@" -c \
-	  -std=c++14 \
-		-I${top_dir} \
-		-I${top_dir}/src \
-		-I${bundle_path}/../../virtual/cores/arduino \
-		-I${bundle_path}/KeyboardioHID/src \
-		-I${top_dir}/testing/googletest/googlemock/include \
-		-I${top_dir}/testing/googletest/googletest/include \
-		-DARDUINO=10607 \
-		-DARDUINO_ARCH_VIRTUAL \
-		-DARDUINO_AVR_MODEL01 \
-		'-DKALEIDOSCOPE_HARDWARE_H="Kaleidoscope-Hardware-Model01.h"' \
-		-DKALEIDOSCOPE_VIRTUAL_BUILD=1 \
-		-DKEYBOARDIOHID_BUILD_WITHOUT_HID=1 \
-		-DUSBCON=dummy \
-		-DARDUINO_ARCH_AVR=1 \
-		'-DUSB_PRODUCT="Model 01"' \
-		$<
+	$(COMPILER_WRAPPER) $(call _arduino_prop,compiler.cpp.cmd) \
+		-o "$@" -c -std=c++14 ${shared_includes} ${shared_defines} $<
 
 clean:
 	rm -f -- "${SRC_DIR}/generated-testcase.cpp"