Added some stopwatch tests

tests/CMakeLists.txt

 cmake_minimum_required(VERSION 3.10)
 project(spdlog_utests CXX)
 
-if(NOT TARGET spdlog)
+if (NOT TARGET spdlog)
     # Stand-alone build
     find_package(spdlog REQUIRED)
-endif()
+endif ()
 
 include(../cmake/utils.cmake)
 
 find_package(PkgConfig)
-if(PkgConfig_FOUND)
+if (PkgConfig_FOUND)
     pkg_check_modules(systemd libsystemd)
-endif()
+endif ()
 
 set(SPDLOG_UTESTS_SOURCES
         test_file_helper.cpp
@@ -32,15 +32,16 @@ set(SPDLOG_UTESTS_SOURCES
         test_backtrace.cpp
         test_create_dir.cpp
         test_cfg.cpp
-    test_time_point.cpp)
+        test_time_point.cpp
+        test_stopwatch.cpp)
 
-if(NOT SPDLOG_NO_EXCEPTIONS)
+if (NOT SPDLOG_NO_EXCEPTIONS)
     list(APPEND SPDLOG_UTESTS_SOURCES test_errors.cpp)
-endif()
+endif ()
 
-if(systemd_FOUND)
+if (systemd_FOUND)
     list(APPEND SPDLOG_UTESTS_SOURCES test_systemd.cpp)
-endif()
+endif ()
 
 enable_testing()
 
@@ -48,22 +49,22 @@ function(spdlog_prepare_test test_target spdlog_lib)
     add_executable(${test_target} ${SPDLOG_UTESTS_SOURCES})
     spdlog_enable_warnings(${test_target})
     target_link_libraries(${test_target} PRIVATE ${spdlog_lib})
-    if(systemd_FOUND)
+    if (systemd_FOUND)
         target_link_libraries(${test_target} PRIVATE ${systemd_LIBRARIES})
-    endif()
-    if(SPDLOG_SANITIZE_ADDRESS)
+    endif ()
+    if (SPDLOG_SANITIZE_ADDRESS)
         spdlog_enable_sanitizer(${test_target})
-    endif()
+    endif ()
     add_test(NAME ${test_target} COMMAND ${test_target})
     set_tests_properties(${test_target} PROPERTIES RUN_SERIAL ON)
 endfunction()
 
 # The compiled library tests
-if(SPDLOG_BUILD_TESTS OR SPDLOG_BUILD_ALL)
+if (SPDLOG_BUILD_TESTS OR SPDLOG_BUILD_ALL)
     spdlog_prepare_test(spdlog-utests spdlog::spdlog)
-endif()
+endif ()
 
 # The header-only library version tests
-if(SPDLOG_BUILD_TESTS_HO OR SPDLOG_BUILD_ALL)
+if (SPDLOG_BUILD_TESTS_HO OR SPDLOG_BUILD_ALL)
     spdlog_prepare_test(spdlog-utests-ho spdlog::spdlog_header_only)
-endif()
+endif ()

tests/test_stopwatch.cpp

+#include "includes.h"
+#include "test_sink.h"
+#include "spdlog/stopwatch.h"
+
+TEST_CASE("stopwatch1", "[stopwatch]")
+{
+    using std::chrono::milliseconds;
+    milliseconds wait_ms(250);
+    milliseconds tolerance_ms(250);
+
+    spdlog::stopwatch sw;
+    std::this_thread::sleep_for(wait_ms);
+    REQUIRE(sw.elapsed() >= wait_ms);
+    REQUIRE(sw.elapsed() <= wait_ms + tolerance_ms);
+}
+
+TEST_CASE("stopwatch2", "[stopwatch]")
+{
+    using spdlog::sinks::test_sink_st;
+
+    std::chrono::duration<double> wait_duration(0.250);
+    std::chrono::duration<double> tolerance_duration(0.250);
+
+    auto test_sink = std::make_shared<test_sink_st>();
+
+    spdlog::stopwatch sw;
+    spdlog::logger logger("test-stopwatch", test_sink);
+    logger.set_pattern("%v");
+    std::this_thread::sleep_for(wait_duration);
+    logger.info("{}", sw);
+    auto val = std::stod(test_sink->lines()[0]);
+
+    REQUIRE(val >= wait_duration.count());
+    REQUIRE(val <= (wait_duration + tolerance_duration).count());
+}