Add tests for sf::sleep

test/CMakeLists.txt

@@ -36,6 +36,7 @@ set(SYSTEM_SRC
     System/Err.test.cpp
     System/FileInputStream.test.cpp
     System/MemoryInputStream.test.cpp
+    System/Sleep.test.cpp
     System/String.test.cpp
     System/Time.test.cpp
     System/Vector2.test.cpp

test/System/Sleep.test.cpp

@@ -0,0 +1,40 @@
+#include <SFML/System/Sleep.hpp>
+
+// Other 1st party headers
+#include <SFML/System/Time.hpp>
+
+#include <doctest/doctest.h>
+
+#include <chrono>
+
+using namespace std::chrono_literals;
+
+// Specialize StringMaker for std::chrono::duration specializations
+// https://github.com/doctest/doctest/blob/master/doc/markdown/stringification.md#docteststringmakert-specialisation
+namespace doctest
+{
+template <typename Rep, typename Period>
+struct StringMaker<std::chrono::duration<Rep, Period>>
+{
+    static String convert(const std::chrono::duration<Rep, Period>& duration)
+    {
+        return toString(std::chrono::nanoseconds(duration).count()) + "ns";
+    }
+};
+} // namespace doctest
+
+#define CHECK_SLEEP_DURATION(duration)                                     \
+    do                                                                     \
+    {                                                                      \
+        const auto startTime = std::chrono::steady_clock::now();           \
+        sf::sleep((duration));                                             \
+        const auto elapsed = std::chrono::steady_clock::now() - startTime; \
+        CHECK(elapsed >= (duration));                                      \
+    } while (false)
+
+TEST_CASE("[System] sf::sleep")
+{
+    CHECK_SLEEP_DURATION(1ms);
+    CHECK_SLEEP_DURATION(10ms);
+    CHECK_SLEEP_DURATION(100ms);
+}