namespace Amphora.UnitTests
{
    public class Lcg64Tests : UnitTestSharp.TestFixture
    {
        public class NextUInt64Tests : UnitTestSharp.TestFixture
        {
            public void MatchesTheRecurrenceFromSeed42()
            {
                var generator = new Lcg64(42);

                CheckEqual(0x91778aed87ee5eb1UL, generator.NextUInt64());
                CheckEqual(0x39b7f8a5c64cf56cUL, generator.NextUInt64());
                CheckEqual(0x69afc5a5e88b394bUL, generator.NextUInt64());
                CheckEqual(0xa161c43f85f3c87eUL, generator.NextUInt64());
            }

            public void LowestBitAlternates()
            {
                var generator = new Lcg64(42);

                CheckEqual(1UL, generator.NextUInt64() & 1);
                CheckEqual(0UL, generator.NextUInt64() & 1);
                CheckEqual(1UL, generator.NextUInt64() & 1);
                CheckEqual(0UL, generator.NextUInt64() & 1);
            }
        }

        public class NextUInt32Tests : UnitTestSharp.TestFixture
        {
            public void IsTheUpperHalfOfTheNext64BitDraw()
            {
                var generator = new Lcg64(42);

                CheckEqual(0x91778aedU, generator.NextUInt32());
                CheckEqual(0x39b7f8a5U, generator.NextUInt32());
            }
        }
    }
}