fix: address 8-bit output re-review findings

tests/test_shared_utils.c

@@ -1,8 +1,27 @@
 #include "test_shared_utils.h"
 #include "utils.h"
+#include "protocol.h"
 #include "test_utils.h"
 #include <stdlib.h>
 #include <string.h>
+#include <threads.h>
+
+typedef struct {
+  bool eight_bit_output;
+  const char* expected;
+  int failed;
+} EscapeThreadArgs;
+
+static int escape_thread(void* arg) {
+  EscapeThreadArgs* args = arg;
+  for (int i = 0; i < 1000; i++) {
+    char* escaped = output_escape("x\xc3\xa9\n", args->eight_bit_output);
+    if (!escaped || strcmp(escaped, args->expected) != 0)
+      args->failed = 1;
+    free(escaped);
+  }
+  return 0;
+}
 
 void test_shared_utils() {
   char high_bit[] = {'a', (char)0xc3, (char)0xa9, '\n', '\0'};
@@ -13,6 +32,26 @@ void test_shared_utils() {
   EXPECT_EQ_STR(escaped, "a\xc3\xa9\\#012");
   free(escaped);
 
+  ProtocolSession safe_session;
+  ProtocolSession eight_bit_session;
+  protocol_session_init(&safe_session, -1, -1);
+  protocol_session_init(&eight_bit_session, -1, -1);
+  protocol_session_set_8_bit_output(&safe_session, false);
+  protocol_session_set_8_bit_output(&eight_bit_session, true);
+  EXPECT_FALSE(safe_session.eight_bit_output);
+  EXPECT_TRUE(eight_bit_session.eight_bit_output);
+
+  EscapeThreadArgs safe_args = {false, "x\\#303\\#251\\#012", 0};
+  EscapeThreadArgs eight_bit_args = {true, "x\xc3\xa9\\#012", 0};
+  thrd_t safe_thread;
+  thrd_t eight_bit_thread;
+  EXPECT_EQ_INT(thrd_create(&safe_thread, escape_thread, &safe_args), thrd_success);
+  EXPECT_EQ_INT(thrd_create(&eight_bit_thread, escape_thread, &eight_bit_args), thrd_success);
+  EXPECT_EQ_INT(thrd_join(safe_thread, NULL), thrd_success);
+  EXPECT_EQ_INT(thrd_join(eight_bit_thread, NULL), thrd_success);
+  EXPECT_FALSE(safe_args.failed);
+  EXPECT_FALSE(eight_bit_args.failed);
+
   // Test str_dup
   const char* dup_null = str_dup(NULL);
   EXPECT_NULL(dup_null);