test: add support for unit testing

test/unit/Makefile.in

@@ -0,0 +1,42 @@
+TEST_WRAPPER =
+CHRONY_SRCDIR = ../..
+
+CC = @CC@
+CFLAGS = @CFLAGS@
+CPPFLAGS = -I$(CHRONY_SRCDIR) @CPPFLAGS@
+LDFLAGS = @LDFLAGS@ @LIBS@ @EXTRA_LIBS@
+
+SHARED_OBJS = test.o
+
+TEST_OBJS := $(sort $(patsubst %.c,%.o,$(wildcard *.c)))
+TESTS := $(patsubst %.o,%.test,$(filter-out $(SHARED_OBJS),$(TEST_OBJS)))
+
+FILTER_OBJS = %/main.o %/client.o %/getdate.o
+CHRONY_OBJS := $(filter-out $(FILTER_OBJS),$(wildcard $(CHRONY_SRCDIR)/*.o))
+
+all: $(TESTS)
+
+%.test: %.o $(SHARED_OBJS)
+	$(CC) $(CFLAGS) -o $@ $^ $(CHRONY_OBJS:%/$*.o=) $(LDFLAGS)
+
+%.o: %.c
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c $<
+
+check: $(TESTS)
+	@ret=0; \
+	for t in $^; do \
+	  $(TEST_WRAPPER) ./$$t || ret=1; \
+	done; \
+	exit $$ret
+
+clean:
+	rm -f *.o $(TESTS)
+	rm -rf .deps
+
+.deps:
+	@mkdir .deps
+
+.deps/%.d: %.c | .deps
+	@$(CC) -MM $(CPPFLAGS) -MT '$(<:%.c=%.o) $@' $< -o $@
+
+-include $(TEST_OBJS:%.o=.deps/%.d)