Add unittest infrastructure

Makefile

@@ -1,24 +1,39 @@
 RM := rm -rf
 DHCP6RELAY_TARGET := dhcp6relay
+DHCP6RELAY_TEST_TARGET := dhcp6relay-test
 CP := cp
 MKDIR := mkdir
 MV := mv
+FIND := find
+GCOVR := gcovr
+GCOV_FLAGS := -fprofile-use -fprofile-arcs -ftest-coverage -fprofile-generate
 override LDLIBS += -levent -lhiredis -lswsscommon -pthread -lboost_thread -lboost_system
+override LDLIBS_TEST += -lgtest_main -lgtest -pthread -lstdc++fs
 override CPPFLAGS += -Wall -std=c++17 -fPIE -I/usr/include/swss
 override CPPFLAGS += -MMD -MP -MF"$(@:%.o=%.d)" -MT"$(@)"
 PWD := $(shell pwd)
 
-all: $(DHCP6RELAY_TARGET)
+test-targets: CPP_FLAGS = -O0 -Wall -fmessage-length=0 -fPIC $(GCOV_FLAGS)
+
+all: $(DHCP6RELAY_TARGET) $(DHCP6RELAY_TEST_TARGET)
 
 ifneq ($(MAKECMDGOALS),clean)
 -include $(OBJS:%.o=%.d)
 endif
 
 -include src/subdir.mk
+-include test/subdir.mk
 
 $(DHCP6RELAY_TARGET): $(OBJS)
 	$(CXX) $(LDFLAGS) $^ $(LDLIBS) -o $@
 
+$(DHCP6RELAY_TEST_TARGET): $(OBJS_DHCP6RELAY_TEST)
+	$(CC) -lgcov --coverage -o "$(DHCP6RELAY_TEST_TARGET)" $(CPP_FLAGS) $(OBJS_DHCP6RELAY_TEST) $(LDLIBS) $(LDLIBS_TEST)
+	./$(DHCP6RELAY_TEST_TARGET)
+	$(GCOVR) -r ./ --html --html-details -o $(DHCP6RELAY_TEST_TARGET)-result.html
+	$(GCOVR) -r ./ --xml-pretty -o $(DHCP6RELAY_TEST_TARGET)-result.xml
+
+
 install:
 	$(MKDIR) -p $(DESTDIR)/usr/sbin
 	$(MV) $(DHCP6RELAY_TARGET) $(DESTDIR)/usr/sbin
@@ -28,7 +43,10 @@ deinstall:
 	$(RM) -rf $(DESTDIR)/usr/sbin
 
 clean:
-	-$(RM) $(EXECUTABLES) $(OBJS:%.o=%.d) $(OBJS) $(DHCP6RELAY_TARGET)
+	-$(RM) $(EXECUTABLES) $(OBJS:%.o=%.d) $(OBJS) $(DHCP6RELAY_TARGET) $(DHCP6RELAY_TEST_TARGET) $(OBJS_DHCP6RELAY_TEST) *.html *.xml
+	$(FIND) . -name *.gcda -exec rm -f {} \;
+	$(FIND) . -name *.gcno -exec rm -f {} \;
+	$(FIND) . -name *.gcov -exec rm -f {} \;
 	-@echo ' '
 
 .PHONY: all clean dependents

test/subdir.mk

@@ -0,0 +1,4 @@
+OBJS += \
+$(PWD)/src/relay.o \
+$(PWD)/src/configInterface.o \
+$(PWD)/src/main.o