re-work unit test mocking (#400)

Instead of trying to use the linker's --wrap, which just led to more problems
when we want to call the real function, we'll add two defines, MOCK_DEFINE() and
MOCK_DECLARE(), that behave differently when building the unit tests, such that
all wrapped functions are picked up from test/mocks.c instead, regardless of
compilation unit.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/lib/common.h b/lib/common.h
index 7ac865e..d15017a 100644
--- a/lib/common.h
+++ b/lib/common.h
@@ -55,21 +55,22 @@
 #define ROUND_DOWN(x, a)    ((x) & ~((a)-1))
 #define ROUND_UP(x,a)       ROUND_DOWN((x)+(a)-1, a)
 
-#define UNIT_TEST_SYMBOL(x) \
-    typeof(x) __wrap_##x __attribute__((weak, alias(#x)))
-
 #ifdef UNIT_TEST
 
-#define MOCKED(r, f, ...) \
+#define MOCK_DEFINE(f) \
+    (__real_ ## f)
+
+#define MOCK_DECLARE(r, f, ...) \
     r f(__VA_ARGS__); \
     r __real_ ## f(__VA_ARGS__); \
     r __wrap_ ## f(__VA_ARGS__);
 
 #else /* UNIT_TEST */
 
-#define MOCKED(r, f, ...) \
-    r f(__VA_ARGS__); \
-    r __wrap_ ## f(__VA_ARGS__)
+#define MOCK_DEFINE(f) (f)
+
+#define MOCK_DECLARE(r, f, ...) \
+    r f(__VA_ARGS__);
 
 #endif /* UNIT_TEST */