From 7d48bdd2c3dc3e3306f2b9075bd5daa49f3d9b4e Mon Sep 17 00:00:00 2001
From: Paul Kunysch <paul@kunysch.de>
Date: Tue, 27 Apr 2021 14:32:19 +0200
Subject: [PATCH] Test fflush/fwrite error propagation.

---
 tests/CMakeLists.txt     |  11 ++++
 tests/test_io_errors.cpp | 116 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 tests/test_io_errors.cpp

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 7fe4791e..7254117c 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -64,7 +64,18 @@ if(SPDLOG_BUILD_TESTS OR SPDLOG_BUILD_ALL)
     spdlog_prepare_test(spdlog-utests spdlog::spdlog)
 endif()
 
+include(CheckCXXCompilerFlag)
+check_cxx_compiler_flag(-Wl,--wrap=fflush HAVE_WL_WRAP_FLAG)
+if (HAVE_WL_WRAP_FLAG AND NOT SPDLOG_NO_EXCEPTIONS)
+    set(SPDLOG_TEST_IO_ERRORS ON CACHE BOOL
+        "Wrap fwrite/fflush to check error propagation in HO tests. Requires GNU ld.")
+endif()
+
 # The header-only library version tests
 if(SPDLOG_BUILD_TESTS_HO OR SPDLOG_BUILD_ALL)
     spdlog_prepare_test(spdlog-utests-ho spdlog::spdlog_header_only)
+    if(SPDLOG_TEST_IO_ERRORS)
+        target_link_options(spdlog-utests-ho PRIVATE -Wl,--wrap=fflush,--wrap=fwrite)
+        target_sources(spdlog-utests-ho PRIVATE test_io_errors.cpp)
+    endif()
 endif()
diff --git a/tests/test_io_errors.cpp b/tests/test_io_errors.cpp
new file mode 100644
index 00000000..7550fe24
--- /dev/null
+++ b/tests/test_io_errors.cpp
@@ -0,0 +1,116 @@
+/*
+ * This content is released under the MIT License as specified in https://raw.githubusercontent.com/gabime/spdlog/master/LICENSE
+ */
+#include "includes.h"
+#include "spdlog/sinks/stdout_sinks.h"
+#include "spdlog/sinks/stdout_color_sinks.h"
+
+#ifdef SPDLOG_NO_EXCEPTIONS
+#error
+#endif
+
+#define TEST_FILENAME "test_logs/file_helper_test.txt"
+using spdlog::details::file_helper;
+using Catch::Matchers::Contains;
+
+static int mocked_fwrite_errno;
+extern "C" int __real_fwrite(void *ptr, size_t size, size_t nmemb, FILE *stream);
+extern "C" int __wrap_fwrite(void *ptr, size_t size, size_t nmemb, FILE *stream)
+{
+    if (mocked_fwrite_errno)
+    {
+        errno = mocked_fwrite_errno;
+        mocked_fwrite_errno = 0;
+        return 0;
+    }
+    return __real_fwrite(ptr, size, nmemb, stream);
+}
+
+static int mocked_fflush_errno;
+extern "C" int __real_fflush(FILE *stream);
+extern "C" int __wrap_fflush(FILE *stream)
+{
+    if (mocked_fflush_errno)
+    {
+        errno = mocked_fflush_errno;
+        mocked_fflush_errno = 0;
+        return EOF;
+    }
+    return __real_fflush(stream);
+}
+
+TEST_CASE("file_helper_write_error", "[file_helper::write()]]")
+{
+    spdlog::memory_buf_t buffer;
+    fmt::format_to(buffer, "not empty");
+    prepare_logdir();
+    file_helper helper;
+    helper.open(SPDLOG_FILENAME_T(TEST_FILENAME));
+    mocked_fwrite_errno = EIO;
+    CHECK_THROWS(helper.write(buffer));
+    mocked_fwrite_errno = 0;
+}
+
+TEST_CASE("file_helper_flush_error", "[file_helper::flush()]]")
+{
+    prepare_logdir();
+    file_helper helper;
+    helper.open(SPDLOG_FILENAME_T(TEST_FILENAME));
+    mocked_fflush_errno = EIO;
+    CHECK_THROWS(helper.flush());
+    mocked_fflush_errno = 0;
+}
+
+TEST_CASE("stdout_st_flush_error", "[stdout]")
+{
+    auto last_error_msg = std::string{};
+    auto l = spdlog::stdout_logger_st("test");
+    l->set_error_handler([&](const std::string &msg) { last_error_msg = msg; });
+    l->set_pattern("%+");
+    mocked_fflush_errno = EIO;
+    l->info("Test stdout_st fflush error");
+    mocked_fflush_errno = 0;
+    spdlog::drop_all();
+    REQUIRE_THAT(last_error_msg, Contains("flush"));
+    REQUIRE_THAT(last_error_msg, Contains("base"));
+}
+
+TEST_CASE("stderr_st_write_error", "[stdout]")
+{
+    auto last_error_msg = std::string{};
+    auto l = spdlog::stderr_logger_mt("test");
+    l->set_error_handler([&](const std::string &msg) { last_error_msg = msg; });
+    mocked_fwrite_errno = EIO;
+    l->info("Test stderr_mt fwrite error");
+    mocked_fwrite_errno = 0;
+    spdlog::drop_all();
+    REQUIRE_THAT(last_error_msg, Contains("write"));
+    REQUIRE_THAT(last_error_msg, Contains("base"));
+}
+
+TEST_CASE("stdout_color_mt_flush_error", "[stdout]")
+{
+    auto last_error_msg = std::string{};
+    auto l = spdlog::stdout_color_mt("test");
+    l->set_error_handler([&](const std::string &msg) { last_error_msg = msg; });
+    l->set_pattern("%+");
+    mocked_fflush_errno = EIO;
+    l->info("Test stdout_color_mt fflush error");
+    mocked_fflush_errno = 0;
+    spdlog::drop_all();
+    REQUIRE_THAT(last_error_msg, Contains("flush"));
+    REQUIRE_THAT(last_error_msg, Contains("ansi"));
+}
+
+TEST_CASE("stderr_color_st_write_error", "[stdout]")
+{
+    auto last_error_msg = std::string{};
+    auto l = spdlog::stderr_color_st("test");
+    l->set_error_handler([&](const std::string &msg) { last_error_msg = msg; });
+    mocked_fwrite_errno = EIO;
+    l->info("Test stderr_color_st fwrite error");
+    mocked_fwrite_errno = 0;
+    spdlog::drop_all();
+    REQUIRE_THAT(last_error_msg, Contains("write"));
+    REQUIRE_THAT(last_error_msg, Contains("ansi"));
+}