testing: Evaluate expressions only once in EXPECT_EQ_STR().

diff --git a/src/testing.h b/src/testing.h
index 2e4bf05..1bcc276 100644 (file)
--- a/src/testing.h
+++ b/src/testing.h
@@ -56,12 +56,14 @@ static int check_count__ = 0;
 #define OK(cond) OK1(cond, #cond)
 
 #define EXPECT_EQ_STR(expect, actual) do { \
-  if (strcmp (expect, actual) != 0) { \
+  /* Evaluate 'actual' only once. */ \
+  const char *got__ = actual; \
+  if (strcmp (expect, got__) != 0) { \
     printf ("not ok %i - %s = \"%s\", want \"%s\"\n", \
-        ++check_count__, #actual, actual, expect); \
+        ++check_count__, #actual, got__, expect); \
     return (-1); \
   } \
-  printf ("ok %i - %s = \"%s\"\n", ++check_count__, #actual, actual); \
+  printf ("ok %i - %s = \"%s\"\n", ++check_count__, #actual, got__); \
 } while (0)
 
 #define EXPECT_EQ_INT(expect, actual) do { \