diff --git a/platform/embedded/hal_flash_bank_memory.c b/platform/embedded/hal_flash_bank_memory.c
index 2315375b1..36cbb356a 100644
--- a/platform/embedded/hal_flash_bank_memory.c
+++ b/platform/embedded/hal_flash_bank_memory.c
@@ -43,11 +43,6 @@
 #include "stdint.h"
 #include "string.h"
 
-#ifdef BTSTACK_TEST
-#include "stdio.h"
-#include <stdlib.h>	// exit(..)
-#endif
-
 static uint32_t hal_flash_bank_memory_get_size(void * context){
 	hal_flash_bank_memory_t * self = (hal_flash_bank_memory_t *) context;
 	return self->bank_size;
diff --git a/test/ad_parser/Makefile b/test/ad_parser/Makefile
index 6efd14ee5..efe7e1b0f 100644
--- a/test/ad_parser/Makefile
+++ b/test/ad_parser/Makefile
@@ -4,7 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall -I.. -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
+
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
 
diff --git a/test/att_db/Makefile b/test/att_db/Makefile
index 1d8031c4a..b55e858c3 100644
--- a/test/att_db/Makefile
+++ b/test/att_db/Makefile
@@ -4,10 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall \
-		  -I. \
-		  -I${BTSTACK_ROOT}/src
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
 CFLAGS += -I${BTSTACK_ROOT}/3rd-party/rijndael
+CFLAGS += -I.
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/avdtp_util/Makefile b/test/avdtp_util/Makefile
index c6388459a..040b36faf 100644
--- a/test/avdtp_util/Makefile
+++ b/test/avdtp_util/Makefile
@@ -4,10 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall \
-		  -I.. \
-		  -I${BTSTACK_ROOT}/src
-		  
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
+
 VPATH += ${BTSTACK_ROOT}/src
 VPATH += ${BTSTACK_ROOT}/src/classic
 VPATH += ${BTSTACK_ROOT}/platform/posix
diff --git a/test/base64/Makefile b/test/base64/Makefile
index ff1064806..6ee7c8a4c 100644
--- a/test/base64/Makefile
+++ b/test/base64/Makefile
@@ -5,7 +5,9 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I. -I../ -I${BTSTACK_ROOT}/src
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/ble_client/Makefile b/test/ble_client/Makefile
index 90402fa38..00f828502 100644
--- a/test/ble_client/Makefile
+++ b/test/ble_client/Makefile
@@ -4,7 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall -I. -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I.
+
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/btstack_link_key_db/Makefile b/test/btstack_link_key_db/Makefile
index a20625d72..750ae79b2 100644
--- a/test/btstack_link_key_db/Makefile
+++ b/test/btstack_link_key_db/Makefile
@@ -5,12 +5,11 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall \
-		  -I. \
-		  -I.. \
-		  -I${BTSTACK_ROOT}/src \
-		  -I${BTSTACK_ROOT}/platform/posix \
-		  -I${BTSTACK_ROOT}/3rd-party/tinydir
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I${BTSTACK_ROOT}/platform/posix
+CFLAGS += -I${BTSTACK_ROOT}/3rd-party/tinydir
+CFLAGS += -I.
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/btstack_memory/Makefile b/test/btstack_memory/Makefile
index 3847290b7..bacec78d8 100644
--- a/test/btstack_memory/Makefile
+++ b/test/btstack_memory/Makefile
@@ -4,7 +4,9 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall -I${BTSTACK_ROOT}/src
+
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/crypto/Makefile b/test/crypto/Makefile
index 5bd22a7f7..0c968235d 100644
--- a/test/crypto/Makefile
+++ b/test/crypto/Makefile
@@ -36,10 +36,10 @@ build-coverage/%.o: %.c | build-coverage
 build-asan/%.o: %.c | build-asan
 	gcc -c ${CFLAGS_ASAN} $< -o $@
 
-build-coverage/%.cpp.o: %.c | build-coverage
+build-coverage/%.o: %.cpp | build-coverage
 	${CC} -c ${CFLAGS_COVERAGE} $< -o $@
 
-build-asan/%.cpp.o: %.c | build-asan
+build-asan/%.o: %.cpp | build-asan
 	${CC} -c ${CFLAGS_ASAN} $< -o $@
 
 
@@ -55,7 +55,7 @@ build-coverage/ecc_micro_ecc: build-coverage/ecc_micro_ecc.o build-coverage/uECC
 build-coverage/aes_cmac_test: build-coverage/aes_cmac_test.o build-coverage/aes_cmac.o build-coverage/rijndael.o | build-coverage
 	${CC} $^ ${LDFLAGS_COVERAGE} -o $@
 
-build-coverage/aes_cmac_test2: build-coverage/aes_cmac_test2.cpp.o build-coverage/btstack_crypto.o  build-coverage/btstack_linked_list.o  build-coverage/hci_cmd.o  build-coverage/btstack_util.o  build-coverage/hci_dump.o  build-coverage/rijndael.o | build-asan
+build-coverage/aes_cmac_test2: build-coverage/aes_cmac_test2.o build-coverage/btstack_crypto.o  build-coverage/btstack_linked_list.o  build-coverage/hci_cmd.o  build-coverage/btstack_util.o  build-coverage/hci_dump.o  build-coverage/rijndael.o | build-asan
 	${CC} $^ ${LDFLAGS_COVERAGE} -o $@
 
 
@@ -71,7 +71,7 @@ build-asan/ecc_micro_ecc: build-asan/ecc_micro_ecc.o build-asan/uECC.o | build-a
 build-asan/aes_cmac_test: build-asan/aes_cmac_test.o build-asan/aes_cmac.o build-asan/rijndael.o | build-asan
 	${CC} $^  ${LDFLAGS_ASAN} -o $@
 
-build-asan/aes_cmac_test2: build-asan/aes_cmac_test2.cpp.o build-asan/btstack_crypto.o  build-asan/btstack_linked_list.o  build-asan/hci_cmd.o  build-asan/btstack_util.o  build-asan/hci_dump.o  build-asan/rijndael.o | build-asan
+build-asan/aes_cmac_test2: build-asan/aes_cmac_test2.o build-asan/btstack_crypto.o  build-asan/btstack_linked_list.o  build-asan/hci_cmd.o  build-asan/btstack_util.o  build-asan/hci_dump.o  build-asan/rijndael.o | build-asan
 	${CC} $^ ${LDFLAGS_ASAN} -o $@
 
 test: all
diff --git a/test/crypto/aes_cmac_test2.c b/test/crypto/aes_cmac_test2.cpp
similarity index 100%
rename from test/crypto/aes_cmac_test2.c
rename to test/crypto/aes_cmac_test2.cpp
diff --git a/test/des_iterator/Makefile b/test/des_iterator/Makefile
index 811860729..da8425513 100644
--- a/test/des_iterator/Makefile
+++ b/test/des_iterator/Makefile
@@ -4,7 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall -I.. -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
+
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/embedded/Makefile b/test/embedded/Makefile
index 78834e39d..b2834f82f 100644
--- a/test/embedded/Makefile
+++ b/test/embedded/Makefile
@@ -4,10 +4,10 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall \
-		  -I. \
-		  -I${BTSTACK_ROOT}/src \
-		  -I${BTSTACK_ROOT}/platform/embedded
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I${BTSTACK_ROOT}/platform/embedded
+CFLAGS += -I.
 		  
 CFLAGS += -DHAVE_HAL_AUDIO
 
diff --git a/test/flash_tlv/Makefile b/test/flash_tlv/Makefile
index b277af3ae..b2620f4cb 100644
--- a/test/flash_tlv/Makefile
+++ b/test/flash_tlv/Makefile
@@ -17,17 +17,11 @@ VPATH = \
 	${BTSTACK_ROOT}/platform/embedded \
 	${BTSTACK_ROOT}/platform/posix \
 
-CFLAGS  = \
-    -DBTSTACK_TEST \
-    -g \
-    -Wall \
-    -Wmissing-prototypes \
-    -Wnarrowing \
-    -I. \
-    -I.. \
-    -I${BTSTACK_ROOT}/src \
-    -I${BTSTACK_ROOT}/platform/embedded \
-    -I${BTSTACK_ROOT}/platform/posix \
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I${BTSTACK_ROOT}/platform/embedded
+CFLAGS += -I${BTSTACK_ROOT}/platform/posix
+CFLAGS += -I..
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
 CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
diff --git a/test/gatt_server/Makefile b/test/gatt_server/Makefile
index b17df0e25..a1598fdc7 100644
--- a/test/gatt_server/Makefile
+++ b/test/gatt_server/Makefile
@@ -1,13 +1,14 @@
-CC = g++
-
 # Requirements: cpputest.github.io
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -DUNIT_TEST -g -Wall -Wnarrowing -Wconversion-null -I. -I../ 
-CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS  = -DUNIT_TEST  -g -Wall -Wnarrowing -Wconversion-null
 CFLAGS += -I${BTSTACK_ROOT}/3rd-party/rijndael
 CFLAGS += -I${BTSTACK_ROOT}/3rd-party/micro-ecc
+CFLAGS += -I${BTSTACK_ROOT}/platform/embedded
+CFLAGS += -I${BTSTACK_ROOT}/platform/posix
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I.
 
 VPATH += ${BTSTACK_ROOT}/src
 VPATH += ${BTSTACK_ROOT}/src/ble 
@@ -49,8 +50,8 @@ LDFLAGS += -lCppUTest -lCppUTestExt
 LDFLAGS_COVERAGE = ${LDFLAGS} -fprofile-arcs -ftest-coverage
 LDFLAGS_ASAN     = ${LDFLAGS} -fsanitize=address
 
-COMMON_OBJ_COVERAGE = $(addprefix build-coverage/,$(COMMON:.c=.o)) build-coverage/uECC.c.o
-COMMON_OBJ_ASAN     = $(addprefix build-asan/,    $(COMMON:.c=.o)) build-asan/uECC.c.o
+COMMON_OBJ_COVERAGE = $(addprefix build-coverage/,$(COMMON:.c=.o)) build-coverage/uECC.o
+COMMON_OBJ_ASAN     = $(addprefix build-asan/,    $(COMMON:.c=.o)) build-asan/uECC.o
 
 
 all: build-coverage/gatt_server_test build-asan/gatt_server_test
@@ -63,23 +64,22 @@ build-%/profile.h: profile.gatt | build-%
 	python3 ${BTSTACK_ROOT}/tool/compile_gatt.py $< $@
 
 build-coverage/%.o: %.c | build-coverage
-	${CC} -c $(CFLAGS_COVERAGE) $< -o $@
-
-build-coverage/%.c.o: %.c | build-coverage
 	gcc -c $(CFLAGS_COVERAGE) $< -o $@
 
-build-asan/%.o: %.c | build-asan
-	${CC} -c $(CFLAGS_ASAN) $< -o $@
+build-coverage/%.o: %.cpp | build-coverage
+	g++ -c $(CFLAGS_COVERAGE) $< -o $@
 
-build-asan/%.c.o: %.c | build-asan
+build-asan/%.o: %.c | build-asan
 	gcc -c $(CFLAGS_ASAN) $< -o $@
 
+build-asan/%.o: %.cpp | build-asan
+	g++ -c $(CFLAGS_ASAN) $< -o $@
 
 build-coverage/gatt_server_test: ${COMMON_OBJ_COVERAGE} build-coverage/profile.h build-coverage/gatt_server_test.o | build-coverage
-	${CC} $(filter-out build-coverage/profile.h,$^) ${LDFLAGS_COVERAGE} -o $@
+	g++ $(filter-out build-coverage/profile.h,$^) ${LDFLAGS_COVERAGE} -o $@
 
 build-asan/gatt_server_test: ${COMMON_OBJ_ASAN} build-asan/profile.h build-asan/gatt_server_test.o | build-asan
-	${CC} $(filter-out build-asan/profile.h,$^) ${LDFLAGS_ASAN} -o $@
+	g++ $(filter-out build-asan/profile.h,$^) ${LDFLAGS_ASAN} -o $@
 
 test: all
 	build-asan/gatt_server_test
diff --git a/test/gatt_server/gatt_server_test.c b/test/gatt_server/gatt_server_test.cpp
similarity index 98%
rename from test/gatt_server/gatt_server_test.c
rename to test/gatt_server/gatt_server_test.cpp
index a2506fc79..32bbcc772 100644
--- a/test/gatt_server/gatt_server_test.c
+++ b/test/gatt_server/gatt_server_test.cpp
@@ -27,7 +27,7 @@ static uint8_t battery_level = 100;
 static const uint8_t uuid128_with_bluetooth_base[] = { 0x00, 0x00, 0xBB, 0xBB, 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB};
 static const uint8_t uuid128_no_bluetooth_base[] =   { 0xFB, 0x34, 0x9B, 0x5F, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0xAA, 0xAA, 0x00, 0x00 };
 
-void l2cap_can_send_fixed_channel_packet_now_set_status(uint8_t status);
+extern "C" void l2cap_can_send_fixed_channel_packet_now_set_status(uint8_t status);
 
 static uint16_t att_read_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
     UNUSED(connection_handle);
diff --git a/test/gatt_server/mock.c b/test/gatt_server/mock.c
index 6a5de94d2..940ddd66d 100644
--- a/test/gatt_server/mock.c
+++ b/test/gatt_server/mock.c
@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include "hci.h"
+#include "gap.h"
 #include "hci_dump.h"
 #include "l2cap.h"
 
@@ -50,7 +51,7 @@ void gap_start_scan(void){
 }
 void gap_stop_scan(void){
 }
-uint8_t gap_connect(bd_addr_t addr, bd_addr_type_t addr_type){
+uint8_t gap_connect(const bd_addr_t addr, bd_addr_type_t addr_type){
 	return 0;
 }
 void gap_set_scan_parameters(uint8_t scan_type, uint16_t scan_interval, uint16_t scan_window){
@@ -191,7 +192,7 @@ void * btstack_run_loop_get_timer_context(btstack_timer_source_t *ts){
 }
 
 // todo:
-hci_connection_t * hci_connection_for_bd_addr_and_type(bd_addr_t addr, bd_addr_type_t addr_type){
+hci_connection_t * hci_connection_for_bd_addr_and_type(const bd_addr_t addr, bd_addr_type_t addr_type){
 	printf("hci_connection_for_bd_addr_and_type not implemented in mock backend\n");
 	return NULL;
 }
diff --git a/test/gatt_service/Makefile b/test/gatt_service/Makefile
index 18bbcfff4..5bbc7d6de 100644
--- a/test/gatt_service/Makefile
+++ b/test/gatt_service/Makefile
@@ -4,7 +4,9 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null -Ibuild-coverage -I../
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null 
+CFLAGS += -I../
+
 CFLAGS += -I${BTSTACK_ROOT}/src
 CFLAGS += -I${BTSTACK_ROOT}/test/mock
 CFLAGS += -I${BTSTACK_ROOT}/3rd-party/rijndael
@@ -35,8 +37,8 @@ COMMON = \
 	ublox_spp_service_server.c \
 
 
-CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
-CFLAGS_ASAN     = ${CFLAGS} -fsanitize=address -DHAVE_ASSERT
+CFLAGS_COVERAGE = ${CFLAGS} -Ibuild-coverage -fprofile-arcs -ftest-coverage 
+CFLAGS_ASAN     = ${CFLAGS} -Ibuild-asan     -fsanitize=address -DHAVE_ASSERT
 
 LDFLAGS += -lCppUTest -lCppUTestExt
 LDFLAGS_COVERAGE = ${LDFLAGS} -fprofile-arcs -ftest-coverage
diff --git a/test/hfp/Makefile b/test/hfp/Makefile
index da6689386..ee3bffb75 100644
--- a/test/hfp/Makefile
+++ b/test/hfp/Makefile
@@ -40,9 +40,11 @@ MOCK = \
     hci_dump.c     				\
     sdp_util.c	                \
 
-CFLAGS   = -g -Wall -Wmissing-prototypes -Wnarrowing 
-# CFLAGS += -Werror
-CFLAGS  += -I. -I../ -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/src/classic -I${POSIX_ROOT} -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS  += -I. -I../
+CFLAGS  += -I${BTSTACK_ROOT}/src
+CFLAGS  += -I${BTSTACK_ROOT}/src/classic
+CFLAGS  += -I${BTSTACK_ROOT}/platform/posix
 # CFLAGS  += -D OCTAVE_OUTPUT
 
 CFLAGS_COVERAGE = ${CFLAGS} -fprofile-arcs -ftest-coverage
diff --git a/test/hid_parser/Makefile b/test/hid_parser/Makefile
index 406c9dabf..1aab60375 100644
--- a/test/hid_parser/Makefile
+++ b/test/hid_parser/Makefile
@@ -4,10 +4,12 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CPPFLAGS =  -x c++ -Wall -Wno-unused
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+
+CFLAGS += -I.
+CFLAGS += -I ${BTSTACK_ROOT}/src
+CFLAGS += -I ${BTSTACK_ROOT}/platform/posix
 
-CFLAGS  = -DUNIT_TEST -g
-CFLAGS += -I. -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/platform/posix
 VPATH += ${BTSTACK_ROOT}/src ${BTSTACK_ROOT}/platform/posix
 
 COMMON = \
diff --git a/test/linked_list/Makefile b/test/linked_list/Makefile
index aebe6d762..e34a28a87 100644
--- a/test/linked_list/Makefile
+++ b/test/linked_list/Makefile
@@ -5,7 +5,10 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I. -I../ -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I${BTSTACK_ROOT}/include
+CFLAGS += -I..
 
 VPATH += ${BTSTACK_ROOT}/src/ble 
 VPATH += ${BTSTACK_ROOT}/src
diff --git a/test/map_test/Makefile b/test/map_test/Makefile
index 42b7571d8..3de18f7c6 100644
--- a/test/map_test/Makefile
+++ b/test/map_test/Makefile
@@ -5,7 +5,10 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I. -I../ -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
+
 LDFLAGS += -lCppUTest -lCppUTestExt
 
 VPATH += ${BTSTACK_ROOT}/src/ble 
diff --git a/test/obex/Makefile b/test/obex/Makefile
index 081992aa3..ab15d21a6 100644
--- a/test/obex/Makefile
+++ b/test/obex/Makefile
@@ -5,7 +5,10 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I. -I../ -I${BTSTACK_ROOT}/src -I${BTSTACK_ROOT}/include
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src 
+CFLAGS += -I../ 
+
 LDFLAGS += -lCppUTest -lCppUTestExt
 
 VPATH += ${BTSTACK_ROOT}/src/ble 
diff --git a/test/ring_buffer/Makefile b/test/ring_buffer/Makefile
index 102bc3ea1..9959b2f71 100644
--- a/test/ring_buffer/Makefile
+++ b/test/ring_buffer/Makefile
@@ -5,7 +5,9 @@ CC=g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I. -I../ -I${BTSTACK_ROOT}/src
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
 LDFLAGS += -lCppUTest -lCppUTestExt
 
 VPATH += ${BTSTACK_ROOT}/src
diff --git a/test/sdp/Makefile b/test/sdp/Makefile
index 72b56c6b9..e584d7ae8 100644
--- a/test/sdp/Makefile
+++ b/test/sdp/Makefile
@@ -4,9 +4,9 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -g -Wall \
-		  -I.. \
-		  -I${BTSTACK_ROOT}/src \
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
 
 LDFLAGS += -lCppUTest -lCppUTestExt 
 
diff --git a/test/sdp_client/Makefile b/test/sdp_client/Makefile
index 1075d2944..f1f508ad5 100644
--- a/test/sdp_client/Makefile
+++ b/test/sdp_client/Makefile
@@ -5,7 +5,10 @@ CC = g++
 BTSTACK_ROOT =  ../..
 CPPUTEST_HOME = ${BTSTACK_ROOT}/test/cpputest
 
-CFLAGS  = -g -Wall -I.. -I${BTSTACK_ROOT}/src
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I..
+
 LDFLAGS += -lCppUTest -lCppUTestExt
 
 VPATH += ${BTSTACK_ROOT}/src/classic 
diff --git a/test/security_manager/Makefile b/test/security_manager/Makefile
index 66b5d1dd6..1bd3defa0 100644
--- a/test/security_manager/Makefile
+++ b/test/security_manager/Makefile
@@ -4,8 +4,7 @@ CC = g++
 
 BTSTACK_ROOT =  ../..
 
-CFLAGS  = -DUNIT_TEST -g
-CFLAGS += -Wall -Wno-unused
+CFLAGS  = -DUNIT_TEST -g -Wall -Wnarrowing -Wconversion-null
 CFLAGS += -I. -I.. -I${BTSTACK_ROOT}/src
 CFLAGS += -I${BTSTACK_ROOT}/platform/embedded
 CFLAGS += -I${BTSTACK_ROOT}/platform/posix
@@ -45,8 +44,8 @@ LDFLAGS += -lCppUTest -lCppUTestExt
 LDFLAGS_COVERAGE = ${LDFLAGS} -fprofile-arcs -ftest-coverage
 LDFLAGS_ASAN     = ${LDFLAGS} -fsanitize=address
 
-COMMON_OBJ_COVERAGE = $(addprefix build-coverage/,$(COMMON:.c=.o)) build-coverage/uECC.c.o
-COMMON_OBJ_ASAN     = $(addprefix build-asan/,    $(COMMON:.c=.o)) build-asan/uECC.c.o
+COMMON_OBJ_COVERAGE = $(addprefix build-coverage/,$(COMMON:.c=.o)) build-coverage/uECC.o
+COMMON_OBJ_ASAN     = $(addprefix build-asan/,    $(COMMON:.c=.o)) build-asan/uECC.o
 
 all: build-coverage/security_manager build-asan/security_manager
 
@@ -54,17 +53,17 @@ build-%:
 	mkdir -p $@
 
 build-coverage/%.o: %.c | build-coverage
-	${CC} -c $(CFLAGS_COVERAGE) $< -o $@
-
-build-coverage/%.c.o: %.c | build-coverage
 	gcc -c $(CFLAGS_COVERAGE) $< -o $@
 
-build-asan/%.o: %.c | build-asan
-	${CC} -c $(CFLAGS_ASAN) $< -o $@
+build-coverage/%.o: %.cpp | build-coverage
+	${CC} -c $(CFLAGS_COVERAGE) $< -o $@
 
-build-asan/%.c.o: %.c | build-asan
+build-asan/%.o: %.c | build-asan
 	gcc -c $(CFLAGS_ASAN) $< -o $@
 
+build-asan/%.o: %.cpp | build-asan
+	${CC} -c $(CFLAGS_ASAN) $< -o $@
+
 
 build-coverage/security_manager: ${COMMON_OBJ_COVERAGE} build-coverage/security_manager.o | build-coverage
 	${CC} $^ ${LDFLAGS_COVERAGE} -o $@
diff --git a/test/security_manager/mock.c b/test/security_manager/mock.c
index 2e8622819..f3f55c331 100644
--- a/test/security_manager/mock.c
+++ b/test/security_manager/mock.c
@@ -24,7 +24,7 @@ static btstack_linked_list_t     event_packet_handlers;
 
 void mock_init(void){
 	the_connection.item.next = NULL;
-	connections = (btstack_linked_item*) &the_connection;
+	connections = (btstack_linked_item_t*) &the_connection;
 }
 
 uint8_t * mock_packet_buffer(void){
@@ -142,7 +142,7 @@ int hci_can_send_packet_now_using_packet_buffer(uint8_t packet_type){
 	return 1;
 }
 
-hci_connection_t * hci_connection_for_bd_addr_and_type(bd_addr_t addr, bd_addr_type_t addr_type){
+hci_connection_t * hci_connection_for_bd_addr_and_type(const bd_addr_t addr, bd_addr_type_t addr_type){
 	return &the_connection;
 }
 hci_connection_t * hci_connection_for_handle(hci_con_handle_t con_handle){
@@ -176,7 +176,7 @@ uint16_t hci_get_manufacturer(void){
 void hci_le_set_own_address_type(uint8_t own_address){
 }
 
-extern "C" void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t cid){
+void l2cap_request_can_send_fix_channel_now_event(hci_con_handle_t con_handle, uint16_t cid){
 	if (packet_buffer_len) return;
     uint8_t event[] = { L2CAP_EVENT_CAN_SEND_NOW, 2, 0, 0};
     little_endian_store_16(event, 2, cid);
diff --git a/test/security_manager/security_manager.c b/test/security_manager/security_manager.cpp
similarity index 97%
rename from test/security_manager/security_manager.c
rename to test/security_manager/security_manager.cpp
index 498dc450c..a1a1f66c3 100644
--- a/test/security_manager/security_manager.c
+++ b/test/security_manager/security_manager.cpp
@@ -109,16 +109,18 @@ bd_addr_t test_device_addr = {0x34, 0xb1, 0xf7, 0xd1, 0x77, 0x9b};
 
 static btstack_packet_callback_registration_t sm_event_callback_registration;
 
-void mock_init(void);
-void mock_simulate_hci_state_working(void);
-void mock_simulate_hci_event(uint8_t * packet, uint16_t size);
-void aes128_report_result(void);
-void mock_simulate_sm_data_packet(uint8_t * packet, uint16_t size);
-void mock_simulate_command_complete(const hci_cmd_t *cmd);
-void mock_simulate_connected(void);
-uint8_t * mock_packet_buffer(void);
-uint16_t mock_packet_buffer_len(void);
-void mock_clear_packet_buffer(void);
+extern "C" {
+    void mock_init(void);
+    void mock_simulate_hci_state_working(void);
+    void mock_simulate_hci_event(uint8_t * packet, uint16_t size);
+    void aes128_report_result(void);
+    void mock_simulate_sm_data_packet(uint8_t * packet, uint16_t size);
+    void mock_simulate_command_complete(const hci_cmd_t *cmd);
+    void mock_simulate_connected(void);
+    uint8_t * mock_packet_buffer(void);
+    uint16_t mock_packet_buffer_len(void);
+    void mock_clear_packet_buffer(void);
+}
 
 void app_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
     uint16_t aHandle;
diff --git a/test/tlv_posix/Makefile b/test/tlv_posix/Makefile
index f99804f94..c57f6a5fb 100644
--- a/test/tlv_posix/Makefile
+++ b/test/tlv_posix/Makefile
@@ -16,15 +16,11 @@ VPATH = \
 	${BTSTACK_ROOT}/src/ble \
 	${BTSTACK_ROOT}/platform/posix \
 
-CFLAGS  = \
-    -DBTSTACK_TEST \
-    -g \
-    -Wall \
-    -Wnarrowing \
-    -I. \
-    -I.. \
-    -I${BTSTACK_ROOT}/src \
-    -I${BTSTACK_ROOT}/platform/posix \
+
+CFLAGS  = -DUNIT_TEST -x c++ -g -Wall -Wnarrowing -Wconversion-null
+CFLAGS += -I${BTSTACK_ROOT}/src
+CFLAGS += -I${BTSTACK_ROOT}/platform/posix
+CFLAGS += -I..
 
 LDFLAGS += -lCppUTest -lCppUTestExt