tests: Add debug helper for printing buffers

Author: real-or-random

src/tests.c

@@ -44,6 +44,22 @@ static int all_bytes_equal(const void* s, unsigned char value, size_t n) {
     return 1;
 }
 
+/* Debug helper for printing arrays of unsigned char. */
+static void print_buf(const unsigned char *buf, size_t len) {
+    size_t i = 0;
+    printf("{");
+    while (i < len) {
+        if (i % 8 == 0) {
+            printf("\n    ");
+        } else {
+            printf(" ");
+        }
+        printf("0x%02X,", buf[i]);
+        i++;
+    }
+    printf("\n}\n");
+}
+
 /* TODO Use CHECK_ILLEGAL(_VOID) everywhere and get rid of the uncounting callback */
 /* CHECK that expr_or_stmt calls the illegal callback of ctx exactly once
  *