Detect and suppress bug message from zlib compression bomb test

src/test/log_test_helpers.h

@@ -35,6 +35,13 @@ int mock_saved_log_has_entry(void);
   tt_assert_msg(mock_saved_log_has_message_containing(str), \
                 "expected log to contain " # str);
 
+#define expect_single_log_msg_containing(str) \
+  do {                                                        \
+    tt_assert_msg(mock_saved_log_has_message_containing(str), \
+                  "expected log to contain " # str);          \
+    tt_int_op(smartlist_len(mock_saved_logs()), OP_EQ, 1);    \
+  } while (0);
+
 #define expect_no_log_msg(str) \
   tt_assert_msg(!mock_saved_log_has_message(str), \
                 "expected log to not contain " # str);

src/test/test_util.c

@@ -2216,10 +2216,17 @@ test_util_gzip_compression_bomb(void *arg)
   size_t result_len = 0;
   tor_zlib_state_t *state = NULL;
 
+
   /* Make sure we can't produce a compression bomb */
+  const int prev_level = setup_full_capture_of_logs(LOG_WARN);
   tt_int_op(-1, OP_EQ, tor_gzip_compress(&result, &result_len,
                                          one_mb, one_million,
                                          ZLIB_METHOD));
+  expect_single_log_msg_containing(
+         "We compressed something and got an insanely high "
+         "compression factor; other Tors would think this "
+         "was a zlib bomb.");
+  teardown_capture_of_logs(prev_level);
 
   /* Here's a compression bomb that we made manually. */
   const char compression_bomb[1039] =
@@ -5464,7 +5471,7 @@ struct testcase_t util_tests[] = {
   UTIL_LEGACY(strmisc),
   UTIL_LEGACY(pow2),
   UTIL_LEGACY(gzip),
-  UTIL_LEGACY(gzip_compression_bomb),
+  UTIL_TEST(gzip_compression_bomb, TT_FORK),
   UTIL_LEGACY(datadir),
   UTIL_LEGACY(memarea),
   UTIL_LEGACY(control_formats),