tests: add Sanity test for SplitFilename83

fix test

fix test

src/tests/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_executable(tests
     common/bit_field.cpp
+    common/file_util.cpp
     common/param_package.cpp
     core/arm/arm_test_common.cpp
     core/arm/arm_test_common.h

src/tests/common/file_util.cpp

@@ -0,0 +1,28 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <array>
+#include <string>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include "common/string_util.h"
+#include "common/file_util.h"
+#include "common/string_util.h"
+
+TEST_CASE("SplitFilename83 Sanity", "[common]") {
+
+    std::string filename = "long_ass_file_name.3ds";
+    std::array<char, 9> short_name;
+    std::array<char, 4> extension;
+
+    FileUtil::SplitFilename83(filename, short_name, extension);
+
+    filename = Common::ToUpper(filename);
+    std::string expected_short_name = filename.substr(0, 6).append("~1");
+    std::string expected_extension = filename.substr(filename.find('.') + 1, 3);
+
+    REQUIRE(memcmp(short_name.data(), expected_short_name.data(), short_name.size()) == 0);
+    REQUIRE(memcmp(extension.data(), expected_extension.data(), extension.size()) == 0);
+}