preserve transport outage validation evidence

tests/protocol_fixture.c

@@ -3,6 +3,12 @@
 
 #include "trikke_protocol.h"
 
+static int fail(int code, const char *message)
+{
+    fprintf(stderr, "protocol fixture failure %d: %s\n", code, message);
+    return code;
+}
+
 int main(void)
 {
     uint8_t packet[TRIKKE_WIRE_MAX_PACKET_SIZE] = {0};
@@ -20,7 +26,7 @@ int main(void)
     size_t size = trikke_encode_metadata_packet(
         packet, sizeof(packet), 41, 1234567, 2, 3, &metadata);
     if (size == 0 || fwrite(packet, 1, size, stdout) != size) {
-        return 1;
+        return fail(1, "metadata encoding or output");
     }
 
     const trikke_wire_sample_t samples[] = {
@@ -52,7 +58,7 @@ int main(void)
     size = trikke_encode_sample_packet(packet, sizeof(packet), 42, 2, 3,
                                        samples, 2);
     if (size == 0 || fwrite(packet, 1, size, stdout) != size) {
-        return 1;
+        return fail(2, "basic sample encoding or output");
     }
 
     trikke_wire_sample_t full_packet[TRIKKE_WIRE_MAX_RECORDS] = {0};
@@ -69,7 +75,7 @@ int main(void)
         TRIKKE_WIRE_MAX_RECORDS);
     if (size != TRIKKE_WIRE_MAX_PACKET_SIZE ||
         fwrite(packet, 1, size, stdout) != size) {
-        return 2;
+        return fail(3, "maximum-size sample encoding or output");
     }
 
     const trikke_wire_sample_t saturated[] = {
@@ -79,13 +85,13 @@ int main(void)
     size = trikke_encode_sample_packet(packet, sizeof(packet), 44, 2, 3,
                                        saturated, 2);
     if (size == 0 || fwrite(packet, 1, size, stdout) != size) {
-        return 3;
+        return fail(4, "saturated timestamp encoding or output");
     }
 
     if (!trikke_wire_timestamp_delta_fits(0, 655350) ||
         trikke_wire_timestamp_delta_fits(0, 655351) ||
         trikke_wire_timestamp_delta_fits(1, 0)) {
-        return 4;
+        return fail(5, "timestamp-delta boundary contract");
     }
     if (trikke_encode_metadata_packet(
             packet, TRIKKE_WIRE_HEADER_SIZE + TRIKKE_WIRE_METADATA_SIZE - 1,
@@ -98,7 +104,7 @@ int main(void)
         trikke_encode_sample_packet(packet, TRIKKE_WIRE_MAX_PACKET_SIZE - 1,
                                     0, 0, 0, full_packet,
                                     TRIKKE_WIRE_MAX_RECORDS) != 0) {
-        return 5;
+        return fail(6, "invalid argument rejection contract");
     }
     return 0;
 }