LoadFile support in Unittests

Source/engine.cpp

@@ -228,7 +228,11 @@ int32_t GenerateRnd(int32_t v)
 size_t GetFileSize(const char *pszName)
 {
 	HANDLE file;
-	SFileOpenFile(pszName, &file);
+	if (!SFileOpenFile(pszName, &file)) {
+		if (!gbQuietMode)
+			app_fatal("GetFileSize - SFileOpenFile failed for file:\n%s", pszName);
+		return 0;
+	}
 	const size_t fileLen = SFileGetFileSize(file);
 	SFileCloseFileThreadSafe(file);
 
@@ -238,7 +242,11 @@ size_t GetFileSize(const char *pszName)
 void LoadFileData(const char *pszName, byte *buffer, size_t fileLen)
 {
 	HANDLE file;
-	SFileOpenFile(pszName, &file);
+	if (!SFileOpenFile(pszName, &file)) {
+		if (!gbQuietMode)
+			app_fatal("LoadFileData - SFileOpenFile failed for file:\n%s", pszName);
+		return;
+	}
 
 	if (fileLen == 0)
 		app_fatal("Zero length SFILE:\n%s", pszName);