Add some extra tests for cheats

- Ensure they're persisted across resets
- Test that they're not applied if invalid
- Test that they're cleared when we ask them to be cleared

src/libretro/core/core.cpp

@@ -231,6 +231,8 @@ void MelonDsDs::CoreState::Reset() {
         memcpy(gbaSram.data(), Console->GetGBASave(), Console->GetGBASaveLength());
     }
 
+    std::vector<melonDS::ARCode> cheats = std::move(Console->AREngine.Cheats);
+
     Console = nullptr;
     melonDS::NDS::Current = nullptr;
     Console = CreateConsole(
@@ -250,6 +252,8 @@ void MelonDsDs::CoreState::Reset() {
         Console->SetGBASave(gbaSram.data(), gbaSram.size());
     }
 
+    Console->AREngine.Cheats = std::move(cheats);
+
     _ndsSramInstalled = false;
     InitFlushFirmwareTask();
 

src/libretro/core/test.cpp

@@ -182,6 +182,15 @@ extern "C" bool melondsds_is_software_renderer() {
     return mode && *mode == RenderMode::Software;
 }
 
+extern "C" unsigned melondsds_num_cheats() {
+    using namespace MelonDsDs;
+    const auto *console = Core.GetConsole();
+    if (!console)
+        return 0;
+
+    return console->AREngine.Cheats.size();
+}
+
 extern "C" retro_proc_address_t MelonDsDs::GetRetroProcAddress(const char* sym) noexcept {
     if (string_is_equal(sym, "libretropy_add_integers"))
         return reinterpret_cast<retro_proc_address_t>(libretropy_add_integers);
@@ -252,6 +261,9 @@ extern "C" retro_proc_address_t MelonDsDs::GetRetroProcAddress(const char* sym)
     if (string_is_equal(sym, "melondsds_is_software_renderer"))
         return reinterpret_cast<retro_proc_address_t>(melondsds_is_software_renderer);
 
+    if (string_is_equal(sym, "melondsds_num_cheats"))
+        return reinterpret_cast<retro_proc_address_t>(melondsds_num_cheats);
+
     return nullptr;
 }
 

test/CMakeLists.txt

@@ -289,6 +289,7 @@ set(MICRECORD_NDS "${CMAKE_CURRENT_SOURCE_DIR}/nds/micrecord.nds")
 
 include(cmake/Basics.cmake)
 include(cmake/Booting.cmake)
+include(cmake/Cheats.cmake)
 include(cmake/Errors.cmake)
 include(cmake/Firmware.cmake)
 include(cmake/Reset.cmake)

test/cmake/Cheats.cmake

@@ -0,0 +1,47 @@
+
+add_python_test(
+    NAME "Cheats persist after retro_reset"
+    TEST_MODULE cheats.persist_after_reset
+    CONTENT "${NDS_ROM}"
+)
+
+add_python_test(
+    NAME "Resetting cheats clears them"
+    TEST_MODULE cheats.cleared_on_cheat_reset
+    CONTENT "${NDS_ROM}"
+)
+
+add_python_test(
+    NAME "Cheats can be updated individually"
+    TEST_MODULE cheats.can_be_updated_individually
+    CONTENT "${NDS_ROM}"
+    DISABLED
+)
+
+
+add_python_test(
+    NAME "Cheats can be disabled individually"
+    TEST_MODULE cheats.can_be_disabled_individually
+    CONTENT "${NDS_ROM}"
+    DISABLED
+)
+
+add_python_test(
+    NAME "Cheats can be toggled on the error screen"
+    TEST_MODULE cheats.can_be_toggled_on_error_screen
+    CONTENT "${NDS_ROM}"
+    DISABLED
+)
+
+add_python_test(
+    NAME "Invalid cheats are not enabled"
+    TEST_MODULE cheats.not_enabled_if_invalid
+    CONTENT "${NDS_ROM}"
+)
+
+add_python_test(
+    NAME "Cheats can be disabled if they're invalid"
+    TEST_MODULE cheats.can_be_disabled_if_invalid
+    CONTENT "${NDS_ROM}"
+    DISABLED
+)

test/python/cheats/cleared_on_cheat_reset.py

@@ -0,0 +1,27 @@
+from ctypes import CFUNCTYPE, c_uint
+
+from libretro import Session
+from libretro.h import RETRO_MEMORY_SYSTEM_RAM
+
+import prelude
+
+session: Session
+with prelude.session() as session:
+    memory = session.core.get_memory(RETRO_MEMORY_SYSTEM_RAM)
+
+    assert memory is not None
+
+    num_cheats = session.get_proc_address(b"melondsds_num_cheats", CFUNCTYPE(c_uint))
+
+    session.core.cheat_set(0, True, b'02000000 DEADBEEF')
+
+    cheats = num_cheats()
+    assert cheats == 1, f"Expected 1 cheat, got {cheats}"
+
+    for i in range(60):
+        session.run()
+
+    session.core.cheat_reset()
+
+    cheats = num_cheats()
+    assert cheats == 0, f"Expected 0 cheats, got {cheats}"

test/python/cheats/not_enabled_if_invalid.py

@@ -0,0 +1,12 @@
+from typing import cast
+
+from libretro import Session, LoggerMessageInterface, LogLevel
+
+import prelude
+
+session: Session
+with prelude.session() as session:
+    message = cast(LoggerMessageInterface, session.message)
+    session.core.cheat_set(0, True, b'fgsfds')
+
+    assert message.message_exts[-1].level == LogLevel.WARNING

test/python/cheats/persist_after_reset.py

@@ -0,0 +1,38 @@
+from ctypes import CFUNCTYPE, c_uint
+
+from libretro import Session
+from libretro.h import RETRO_MEMORY_SYSTEM_RAM
+
+import prelude
+
+session: Session
+with prelude.session() as session:
+    memory = session.core.get_memory(RETRO_MEMORY_SYSTEM_RAM)
+
+    assert memory is not None
+
+    num_cheats = session.get_proc_address(b"melondsds_num_cheats", CFUNCTYPE(c_uint))
+
+    session.core.cheat_set(0, True, b'02000000 DEADBEEF')
+    # A trivial cheat code with one instruction: 0XXXXXXX-YYYYYYYY,
+    # where XXXXXXX (in this case, 02000000) is the address to write to
+    # and YYYYYYYY (in this case, DEADBEEF) is the value to write.
+    # See https://mgba-emu.github.io/gbatek/#dscartcheatactionreplayds for more details
+
+    # Slicing reads the bytes in sequence, not as a word
+    assert memory[0:4].tobytes() != b'\xef\xbe\xad\xde'
+
+    # Cheats aren't applied immediately, they're applied when the ARM7 processes a VBlank IRQ
+    # (so we need to run a few frames)
+    for i in range(60):
+        session.run()
+
+    session.reset()
+
+    num_cheats = num_cheats()
+    assert num_cheats == 1, f"Expected 1 cheat, got {num_cheats}"
+
+    for i in range(60):
+        session.run()
+
+    assert memory[0:4].tobytes() == b'\xef\xbe\xad\xde', f"Expected 0xDEADBEEF, got {memory[0:4].tobytes()}"