Catch exceptions from async logger. Fix #2618

tests/test_async.cpp

@@ -185,6 +185,14 @@ TEST_CASE("to_file multi-workers", "[async]")
             logger->info("Hello message #{}", j);
         }
     }
-
     require_message_count(TEST_FILENAME, messages);
 }
+
+TEST_CASE("bad_tp", "[async]")
+{
+    auto test_sink = std::make_shared<spdlog::sinks::test_sink_mt>();
+    std::shared_ptr<spdlog::details::thread_pool> const empty_tp;
+    auto logger = std::make_shared<spdlog::async_logger>("as", test_sink, empty_tp);
+    logger->info("Please throw an exception");
+    REQUIRE(test_sink->msg_counter() == 0);
+}