PolyTraderSharp/tests/PolyTrader.Tests/SellLogicTests.cs

using PolyTrader.Modules.CopyTrading.Logic;
using Xunit;
using static PolyTrader.Modules.CopyTrading.Logic.SellLogic;

namespace PolyTrader.Tests
{
    /// <summary>
    /// Sicherheitsnetz für die SELL-Logik: Proportionalität (aktuelles Verhalten, Phase-2-Umbau)
    /// und die Eskalationsleiter (Phase 0.1 – Preis-Stufen, Floor-Clamping).
    /// </summary>
    public class SellLogicTests
    {
        // ---------------- SellProportion ----------------

        [Fact]
        public void SellProportion_is_share_over_total_before_sell()
        {
            // Master hält noch 300, verkauft 200 -> 200/500 = 0.40
            Assert.Equal(0.40m, SellProportion(masterSharesRemaining: 300m, signalSize: 200m));
        }

        [Fact]
        public void SellProportion_small_partial_is_below_threshold()
        {
            // 498 Rest, 2 verkauft -> 0.004 < 0.30
            var ratio = SellProportion(498m, 2m);
            Assert.True(ratio < MinSignificantSellRatio);
        }

        [Fact]
        public void SellProportion_full_exit_is_one()
        {
            Assert.Equal(1.0m, SellProportion(0m, 10m));
        }

        [Theory]
        [InlineData(0, 0)]     // gar nichts
        [InlineData(-5, 5)]    // Denominator 0
        [InlineData(-10, 5)]   // Denominator negativ
        public void SellProportion_guards_non_positive_denominator(double remaining, double signal)
        {
            Assert.Equal(0m, SellProportion((decimal)remaining, (decimal)signal));
        }

        // ---------------- Eskalationsleiter ----------------

        [Fact]
        public void FirstLimit_normal_trader_applies_percentage_discount()
        {
            // 0.99 * (1 - 2%) = 0.9702
            Assert.Equal(0.9702m, FirstLimit(0.99m, isHf: false, maxPriceDifferencePct: 2m));
        }

        [Fact]
        public void FirstLimit_hf_trader_applies_fixed_half_cent_discount()
        {
            Assert.Equal(0.985m, FirstLimit(0.99m, isHf: true, maxPriceDifferencePct: 99m));
        }

        [Fact]
        public void Floor_is_reference_minus_floor_pct()
        {
            // 0.99 * (1 - 15%) = 0.8415
            Assert.Equal(0.8415m, Floor(0.99m, 15m));
        }

        [Fact]
        public void NextPrice_steps_down_relative_when_above_floor()
        {
            // 0.90 * (1 - 3%) = 0.873, über Floor 0.80
            Assert.Equal(0.873m, NextPrice(0.90m, stepPct: 3m, floor: 0.80m));
        }

        [Fact]
        public void NextPrice_clamps_to_floor()
        {
            // 0.82 * 0.97 = 0.7954 -> unter Floor -> 0.80
            Assert.Equal(0.80m, NextPrice(0.82m, 3m, 0.80m));
        }

        [Fact]
        public void IsAtFloor_is_inclusive()
        {
            Assert.True(IsAtFloor(0.80m, 0.80m));
            Assert.True(IsAtFloor(0.79m, 0.80m));
            Assert.False(IsAtFloor(0.81m, 0.80m));
        }

        [Theory]
        [InlineData(true, 20)]   // HF-Trader: schnelles Nachpreisen
        [InlineData(false, 120)] // Standard
        public void LadderIntervalSeconds_hf_is_faster(bool isHf, int expected)
        {
            Assert.Equal(expected, LadderIntervalSeconds(isHf));
        }

        [Fact]
        public void Ladder_walks_down_in_steps_until_floor()
        {
            // Simuliert den Service: von Startlimit in 3%-Schritten bis zum Floor, dann Stopp.
            decimal reference = 0.99m;
            decimal price = FirstLimit(reference, isHf: false, maxPriceDifferencePct: 2m); // 0.9702
            decimal floor = Floor(reference, 15m); // 0.8415

            int steps = 0;
            while (!IsAtFloor(price, floor) && steps < 100)
            {
                price = NextPrice(price, LadderStepPct, floor);
                steps++;
            }

            Assert.True(IsAtFloor(price, floor));
            Assert.Equal(floor, price);          // endet exakt auf dem Floor (geclamped)
            Assert.InRange(steps, 1, 20);        // terminiert in wenigen Schritten
        }
    }
}