using FluentAssertions; using Xunit; namespace PerfectNumbers.Core.Tests; [Trait("Category", "Fast")] public class MersenneResidueModeTests { [Fact] public void IsMersennePrime_residue_mode_rejects_composite_exponent() { var tester = new MersenneNumberTester(useResidue: true, useIncremental: false); tester.IsMersennePrime(136_000_002UL).Should().BeFalse(); } }