diff --git a/test/bacnet/datalink/mock/CMakeLists.txt b/test/bacnet/datalink/mock/CMakeLists.txt
index 02195e7d..fd831a44 100644
--- a/test/bacnet/datalink/mock/CMakeLists.txt
+++ b/test/bacnet/datalink/mock/CMakeLists.txt
@@ -24,11 +24,13 @@ add_compile_definitions(
 	BIG_ENDIAN=0
 	CONFIG_ZTEST=1
 	BACDL_ALL=1
+	UNIT_TESTING=1
 	)
 
 include_directories(
 	${SRC_DIR}
 	${TST_DIR}/ztest/include
+	./src/
 	)
 
 file(GLOB SRC_TEST ./src/*.c)
@@ -38,6 +40,7 @@ add_executable(${PROJECT_NAME}
 	${SRC_DIR}/bacnet/datalink/datalink.c
 	${SRC_DIR}/../ports/rx62n/bacnet.c
 	# Support files and stubs (pathname alphabetical)
+	${SRC_DIR}/bacnet/basic/sys/mstimer.c
 	${SRC_DIR}/bacnet/bacdcode.c
 	${SRC_DIR}/bacnet/bacint.c
 	${SRC_DIR}/bacnet/bacreal.c
diff --git a/test/bacnet/datalink/mock/src/main.c b/test/bacnet/datalink/mock/src/main.c
index d9f5fbac..b6baf92a 100644
--- a/test/bacnet/datalink/mock/src/main.c
+++ b/test/bacnet/datalink/mock/src/main.c
@@ -430,6 +430,7 @@ static void test_datalink_ethernet(void)
  * @brief Test bacnet.c
  */
 
+#ifdef UNIT_TESTING
 
 uint8_t Handler_Transmit_Buffer[MAX_PDU] = { 0 };
 
@@ -555,6 +556,7 @@ unsigned long mstimer_now(void)
     return l++;
 }
 
+
 void dcc_timer_seconds(uint32_t seconds)
 {
     ztest_check_expected_value(seconds);
@@ -566,10 +568,13 @@ void npdu_handler(BACNET_ADDRESS *src, uint8_t *pdu, uint16_t pdu_len)
     ztest_check_expected_data(pdu, pdu_len);
 }
 
+#endif /* UNIT_TESTING */
+
 //  test
 
 static void test_bacnet_task(void)
 {
+#ifdef UNIT_TESTING
     uint8_t expected_data[MAX_MPDU] = { 0x5A, 0xA5, 0xDE, 0xAD };
     uint8_t expected_data2[MAX_MPDU] = { 0xAA, 0xBB, 0xCC, 0xDD };
 
@@ -590,6 +595,7 @@ static void test_bacnet_task(void)
     ztest_returns_value(arcnet_receive, 0);
     bacnet_task();
     zassert_equal(z_cleanup_mock(), 0, NULL);
+#endif /* UNIT_TESTING */
 }
 
 /**
diff --git a/zephyr/tests/bacnet/datalink/mock/CMakeLists.txt b/zephyr/tests/bacnet/datalink/mock/CMakeLists.txt
index f7a74160..8980e9c2 100644
--- a/zephyr/tests/bacnet/datalink/mock/CMakeLists.txt
+++ b/zephyr/tests/bacnet/datalink/mock/CMakeLists.txt
@@ -25,8 +25,10 @@ get_filename_component(BACNET_SRC ${BACNET_DATALINK_SRC} PATH)
 
 if(BOARD STREQUAL unit_testing)
   file(RELATIVE_PATH BACNET_INCLUDE $ENV{ZEPHYR_BASE} ${BACNET_BASE}/src)
-  list(APPEND INCLUDE ${BACNET_INCLUDE} ${BACNET_INCLUDE}/../test/bacnet/datalink/mock/src)
-  message(STATUS "tdh="${BACNET_TEST_PATH}/src)
+  list(APPEND INCLUDE
+    ${BACNET_INCLUDE}
+    ${BACNET_INCLUDE}/../test/bacnet/datalink/mock/src
+    )
 
   file(GLOB SRC_TEST ${BACNET_TEST_PATH}/src/*.c)
   list(APPEND SOURCES ${SRC_TEST} )
@@ -38,6 +40,7 @@ if(BOARD STREQUAL unit_testing)
     )
 
   add_definitions(-DBACDL_ALL=1)
+  add_definitions(-DUNIT_TESTING=1)
 
   include($ENV{ZEPHYR_BASE}/subsys/testsuite/unittest.cmake)
   project(${BACNET_NAME})
@@ -45,7 +48,10 @@ else()
   include($ENV{ZEPHYR_BASE}/cmake/app/boilerplate.cmake NO_POLICY_SCOPE)
   project(${BACNET_NAME})
 
-  target_include_directories(app PRIVATE ${BACNET_INCLUDE})
+  target_include_directories(app PRIVATE
+    ${BACNET_INCLUDE}
+    ${BACNET_INCLUDE}/../test/bacnet/datalink/mock/src
+    )
   file(GLOB SRC_TEST ${BACNET_TEST_PATH}/src/*.c)
 
   add_definitions(-DBACDL_ALL=1 -DBACNET_ETHERNET_NO_REMAP_DEFINES=1)