mrgameeng/tests/MrGameEng.Core.Tests/CalendarTests.cs

using MrGameEng.Core;
using Xunit;

namespace MrGameEng.Core.Tests;

public class CalendarTests
{
    [Fact]
    public void Constructor_NonPositiveSecondsPerDay_Throws()
    {
        Assert.Throws<ArgumentOutOfRangeException>(() => new Calendar(new GameClock(), 0f));
    }

    [Fact]
    public void TotalDays_TracksScaledClockTime()
    {
        var clock = new GameClock();
        var calendar = new Calendar(clock, secondsPerDay: 10f);

        clock.Advance(5f); // half a day

        Assert.Equal(0.5, calendar.TotalDays, 5);
        Assert.Equal(1, calendar.Day);
        Assert.Equal(0.5f, calendar.DayProgress, 5);
    }

    [Fact]
    public void Day_CountsFromOne_AndRollsOver()
    {
        var clock = new GameClock();
        var calendar = new Calendar(clock, secondsPerDay: 10f);

        Assert.Equal(1, calendar.Day);

        clock.Advance(10f); // exactly one day
        Assert.Equal(2, calendar.Day);
        Assert.Equal(0f, calendar.DayProgress, 5);

        clock.Advance(15f); // total 25s = 2.5 days
        Assert.Equal(3, calendar.Day);
        Assert.Equal(0.5f, calendar.DayProgress, 5);
    }

    [Fact]
    public void Pause_DoesNotAdvanceTheCalendar()
    {
        var clock = new GameClock { TimeScale = 0f };
        var calendar = new Calendar(clock, secondsPerDay: 10f);

        clock.Advance(100f);

        Assert.Equal(0.0, calendar.TotalDays, 5);
        Assert.Equal(1, calendar.Day);
    }

    [Fact]
    public void TimeScale_SpeedsUpTheCalendar()
    {
        var slow = new GameClock();
        var fast = new GameClock { TimeScale = 6f };
        var slowCal = new Calendar(slow, secondsPerDay: 10f);
        var fastCal = new Calendar(fast, secondsPerDay: 10f);

        slow.Advance(10f);
        fast.Advance(10f);

        Assert.Equal(6.0, fastCal.TotalDays / slowCal.TotalDays, 5);
    }
}