Problem: assert macros not detecting errors from syscall that do not return -1 on failure

Solution: add a new TEST_ASSERT_SUCCESS_RAW_ZERO_ERRNO macro so that
it can check explicitly for non-zero values. This will be used
for getaddrinfo().

tests/testutil_unity.cpp

@@ -55,12 +55,10 @@ int test_assert_success_message_errno_helper (int rc_,
     return rc_;
 }
 
-int test_assert_success_message_raw_errno_helper (int rc_,
-                                                  const char *msg_,
-                                                  const char *expr_,
-                                                  int line_)
+int test_assert_success_message_raw_errno_helper (
+  int rc_, const char *msg_, const char *expr_, int line_, bool zero)
 {
-    if (rc_ == -1) {
+    if (rc_ == -1 || (zero && rc_ != 0)) {
 #if defined ZMQ_HAVE_WINDOWS
         int current_errno = WSAGetLastError ();
 #else
@@ -70,14 +68,24 @@ int test_assert_success_message_raw_errno_helper (int rc_,
         char buffer[512];
         buffer[sizeof (buffer) - 1] =
           0; // to ensure defined behavior with VC++ <= 2013
-        snprintf (buffer, sizeof (buffer) - 1, "%s failed%s%s%s, errno = %i",
+        snprintf (
+          buffer, sizeof (buffer) - 1, "%s failed%s%s%s with %d, errno = %i/%s",
           expr_, msg_ ? " (additional info: " : "", msg_ ? msg_ : "",
-                  msg_ ? ")" : "", current_errno);
+          msg_ ? ")" : "", rc_, current_errno, strerror (current_errno));
         UNITY_TEST_FAIL (line_, buffer);
     }
     return rc_;
 }
 
+int test_assert_success_message_raw_zero_errno_helper (int rc_,
+                                                       const char *msg_,
+                                                       const char *expr_,
+                                                       int line_)
+{
+    return test_assert_success_message_raw_errno_helper (rc_, msg_, expr_,
+                                                         line_, true);
+}
+
 int test_assert_failure_message_raw_errno_helper (
   int rc_, int expected_errno_, const char *msg_, const char *expr_, int line_)
 {

tests/testutil_unity.hpp

@@ -43,7 +43,10 @@ int test_assert_success_message_errno_helper (int rc_,
                                               const char *expr_,
                                               int line);
 
-int test_assert_success_message_raw_errno_helper (int rc_,
+int test_assert_success_message_raw_errno_helper (
+  int rc_, const char *msg_, const char *expr_, int line, bool zero_ = false);
+
+int test_assert_success_message_raw_zero_errno_helper (int rc_,
                                                        const char *msg_,
                                                        const char *expr_,
                                                        int line);
@@ -88,9 +91,22 @@ int test_assert_failure_message_raw_errno_helper (
 // A typical use would be:
 //   TEST_ASSERT_SUCCESS_RAW_ERRNO (send (fd, buffer, 64, 0));
 // In case of success, the result of the macro is the result of 'expr'.
+// Success is strictly defined by a return value different from -1, as opposed
+// to checking that it is 0, like TEST_ASSERT_FAILURE_RAW_ZERO_ERRNO does.
 #define TEST_ASSERT_SUCCESS_RAW_ERRNO(expr)                                    \
     test_assert_success_message_raw_errno_helper (expr, NULL, #expr, __LINE__)
 
+// Asserts that the socket API 'expr' is successful. In case of a failure, the
+// assertion message includes the literal 'expr' and the error code.
+// A typical use would be:
+//   TEST_ASSERT_SUCCESS_RAW_ZERO_ERRNO (send (fd, buffer, 64, 0));
+// In case of success, the result of the macro is the result of 'expr'.
+// Success is strictly defined by a return value of 0, as opposed to checking
+// that it is not -1, like TEST_ASSERT_FAILURE_RAW_ERRNO does.
+#define TEST_ASSERT_SUCCESS_RAW_ZERO_ERRNO(expr)                               \
+    test_assert_success_message_raw_zero_errno_helper (expr, NULL, #expr,      \
+                                                       __LINE__)
+
 // Asserts that the socket API 'expr' is not successful, and the error code is
 // 'error_code'. In case of an unexpected succces, or a failure with an
 // unexpected error code, the assertion message includes the literal 'expr'