runtime: encapsulate checkpoint progress state

tests/smoke_auth.cpp

@@ -10,6 +10,7 @@
 #include "game/stdafx.h"
 #include "game/SecureCipher.h"
 #include "libthecore/fdwatch.h"
+#include "libthecore/signal.h"
 
 namespace
 {
@@ -309,6 +310,19 @@ void TestFdwatchBackendMetadata()
 	fdwatch_delete(fdw);
 }
 
+void TestCheckpointBackendMetadata()
+{
+#ifdef OS_WINDOWS
+	Expect(signal_checkpoint_backend() == CHECKPOINT_BACKEND_NONE, "Expected no checkpoint backend on Windows");
+	Expect(std::strcmp(signal_checkpoint_backend_name(signal_checkpoint_backend()), "none") == 0,
+	       "Unexpected checkpoint backend name on Windows");
+#else
+	Expect(signal_checkpoint_backend() == CHECKPOINT_BACKEND_VIRTUAL_TIMER, "Expected virtual timer checkpoint backend");
+	Expect(std::strcmp(signal_checkpoint_backend_name(signal_checkpoint_backend()), "virtual-timer") == 0,
+	       "Unexpected checkpoint backend name");
+#endif
+}
+
 void TestFdwatchSlotReuseAfterDelete()
 {
 	int sockets_a[2] = { -1, -1 };
@@ -358,6 +372,7 @@ int main()
 		TestSecureCipherRoundTrip();
 		TestSocketAuthWireFlow();
 		TestFdwatchBackendMetadata();
+		TestCheckpointBackendMetadata();
 		TestFdwatchReadAndOneshotWrite();
 		TestFdwatchSlotReuseAfterDelete();
 		std::cout << "metin smoke tests passed\n";