ztest: Give error if user has not defined CONFIG_ZTEST

If user is trying to use ztest by including ztest.h but has
not defined CONFIG_ZTEST, then fail the compilation as the
result binary will not do anything.

There is no check for CONFIG_ZTEST for unit tests that are run
without qemu.

Change-Id: Ief9bba3a3a0f6acc6a264f17cde828b6d7e543a5
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

tests/unit/Makefile.unittest

@@ -26,6 +26,7 @@ all: $(TARGET)
 
 ZTEST = tests/ztest/src
 LIB += $(ZTEST)/ztest.o $(ZTEST)/ztest_mock.o
+CFLAGS += -DZTEST_UNITTEST
 
 OBJS = $(addprefix $(O)/, $(OBJECTS) $(LIB))
 

tests/ztest/include/ztest.h

@@ -17,6 +17,10 @@
  * @defgroup ztest Zephyr testing suite
  */
 
+#if !defined(CONFIG_ZTEST) && !defined(ZTEST_UNITTEST)
+#error "You need to add CONFIG_ZTEST to your config file."
+#endif
+
 #ifndef KERNEL
 #define CONFIG_STDOUT_CONSOLE 1
 #define CONFIG_ZTEST_ASSERT_VERBOSE 1