public static void TestInternalChecksumVsExternal()
{
var result = SuperFamiCheckTool.Run(RomFileName);
result.Complement.Should().Be(0x8773);
result.Checksum.Should().Be(0x788c);
(result.Complement + result.Checksum).Should().Be(0xFFFF);
const uint expected4ByteChecksums = 0x788C8773;
result.AllCheckBytes.Should().Be(expected4ByteChecksums);
var project = ImportUtils.ImportRomAndCreateNewProject(RomFileName);
project.Should().NotBeNull("project should have loaded successfully");
project.Data.GetRomByte(0xFFDC).Should().Be(0x73); // complement 1
project.Data.GetRomByte(0xFFDD).Should().Be(0x87); // complement 2
project.Data.GetRomByte(0xFFDE).Should().Be(0x8C); // checksum 1
project.Data.GetRomByte(0xFFDF).Should().Be(0x78); // checksum 2
var complement = project.Data.GetRomWord(0xFFDC);
complement.Should().Be(0x8773); // complement 16bit
var checksum = project.Data.GetRomWord(0xFFDE);
checksum.Should().Be(0x788c); // checksum 16bit
(complement + checksum).Should().Be(0xFFFF);
project.Data.GetRomDoubleWord(0xFFDC).Should().Be((int)expected4ByteChecksums); // complement 16bit
project.Data.RomCheckSumsFromRomBytes.Should().Be(expected4ByteChecksums);
project.InternalCheckSum.Should().Be(expected4ByteChecksums);
result.Complement.Should().Be((uint)complement);
result.Checksum.Should().Be((uint)checksum);
project.Data.ComputeChecksum().Should().Be((ushort)checksum);
project.Data.ComputeIsChecksumValid().Should().Be(true);
var firstByte = project.Data[0x00];
firstByte.Should().NotBe(0);
project.Data[0x00] = 0;
project.Data.ComputeIsChecksumValid().Should().Be(false);
project.Data.FixChecksum();
project.Data.ComputeIsChecksumValid().Should().Be(true);
project.Data[0x00] = firstByte;
project.Data.ComputeIsChecksumValid().Should().Be(false);
project.Data.FixChecksum();
project.Data.ComputeIsChecksumValid().Should().Be(true);
// SNES docs dictate:
// 15. Complement Check (0xFFDC, 0xFFDD)
// 16. Check Sum (0xFFDE, 0xFFDF)
// in the actual ROM file, it appears like this (remember: little endian for SNES)
// complement checksum
// 73 87 8C 78
}