DesktopClock/DesktopClock.Tests/DateTimeTests.cs

using System;

namespace DesktopClock.Tests;

public class DateTimeTests
{
    [Theory]
    [InlineData("2024-07-18T12:30:45.123Z", "2024-07-18T12:30:45.456Z", true)] // Different millisecond
    [InlineData("2024-07-18T12:30:45.123Z", "2024-07-18T12:30:46.123Z", false)] // Different second
    [InlineData("2024-07-18T12:30:45.123Z", "2024-07-18T12:31:45.123Z", false)] // Different minute
    [InlineData("2024-07-18T12:30:45.123Z", "2024-07-18T13:30:45.123Z", false)] // Different hour
    [InlineData("2024-07-18T12:30:45.123Z", "2024-07-19T12:30:45.123Z", false)] // Different day
    [InlineData("2024-07-18T12:30:45.123Z", "2024-08-18T12:30:45.123Z", false)] // Different month
    [InlineData("2024-07-18T12:30:45.123Z", "2025-07-18T12:30:45.123Z", false)] // Different year
    public void EqualExcludingMilliseconds(string dt1String, string dt2String, bool expected)
    {
        // Arrange
        var dt1 = DateTime.Parse(dt1String);
        var dt2 = DateTime.Parse(dt2String);

        // Act
        var result = dt1.EqualExcludingMillisecond(dt2);

        // Assert
        Assert.Equal(expected, result);
    }

    [Fact]
    public void EqualExcludingMilliseconds_SameDateTime_ShouldBeTrue()
    {
        // Arrange
        var dt1 = new DateTime(2024, 7, 18, 12, 30, 45, 123);
        var dt2 = new DateTime(2024, 7, 18, 12, 30, 45, 123);

        // Act
        var result = dt1.EqualExcludingMillisecond(dt2);

        // Assert
        Assert.True(result);
    }

    [Fact]
    public void EqualExcludingMilliseconds_OnlyMillisecondsDiffer_ShouldBeTrue()
    {
        // Arrange
        var dt1 = new DateTime(2024, 7, 18, 12, 30, 45, 0);
        var dt2 = new DateTime(2024, 7, 18, 12, 30, 45, 999);

        // Act
        var result = dt1.EqualExcludingMillisecond(dt2);

        // Assert
        Assert.True(result);
    }

    [Fact]
    public void EqualExcludingMilliseconds_Reflexive_ShouldBeTrue()
    {
        // Arrange
        var dt = DateTime.Now;

        // Act & Assert
        Assert.True(dt.EqualExcludingMillisecond(dt));
    }

    [Fact]
    public void EqualExcludingMilliseconds_Symmetric_ShouldWork()
    {
        // Arrange
        var dt1 = new DateTime(2024, 7, 18, 12, 30, 45, 100);
        var dt2 = new DateTime(2024, 7, 18, 12, 30, 45, 200);

        // Act & Assert
        Assert.Equal(dt1.EqualExcludingMillisecond(dt2), dt2.EqualExcludingMillisecond(dt1));
    }

    [Theory]
    [InlineData("2024-07-18 12:30:00", "2024-07-18 12:30:00", 30, true)] // Countdown reached, on interval
    [InlineData("2024-07-18 12:30:01", "2024-07-18 12:30:01", 30, true)] // Countdown reached, not on interval
    [InlineData("2024-07-18 12:29:00", "2024-07-18 12:30:00", 30, true)] // Not yet reached, on interval
    [InlineData("2024-07-18 12:29:01", "2024-07-18 12:30:01", 30, true)] // Not yet reached, on interval
    [InlineData("2024-07-18 12:29:02", "2024-07-18 12:30:01", 30, false)] // Not yet reached, not on interval
    [InlineData("2024-07-18 12:31:00", "2024-07-18 12:30:00", 30, true)] // Past countdown, on interval
    [InlineData("2024-07-18 12:31:02", "2024-07-18 12:30:01", 30, false)] // Past countdown, not on interval
    public void IsOnInterval(string nowString, string countdownString, int intervalSeconds, bool expected)
    {
        // Arrange
        var dateTime = DateTime.Parse(nowString);
        var countdownTo = DateTime.Parse(countdownString);
        var interval = TimeSpan.FromSeconds(intervalSeconds);

        // Act
        var result = DateTimeUtil.IsNowOrCountdownOnInterval(dateTime, countdownTo, interval);

        // Assert
        Assert.Equal(expected, result);
    }

    [Fact]
    public void IsOnInterval_DefaultCountdown_ShouldUseNowTimeOfDay()
    {
        // Arrange - when countdown is default, it uses now.TimeOfDay
        var now = new DateTime(2024, 7, 18, 12, 30, 0); // 12:30:00 = 45000 seconds
        var countdownTo = default(DateTime);
        var interval = TimeSpan.FromMinutes(30); // 1800 seconds

        // Act
        var result = DateTimeUtil.IsNowOrCountdownOnInterval(now, countdownTo, interval);

        // Assert - 45000 % 1800 = 0, so should be on interval
        Assert.True(result);
    }

    [Fact]
    public void IsOnInterval_DefaultInterval_ShouldReturnFalseUnlessCountdownReached()
    {
        // Arrange
        var now = new DateTime(2024, 7, 18, 12, 30, 0);
        var countdownTo = new DateTime(2024, 7, 18, 12, 35, 0);
        var interval = TimeSpan.Zero;

        // Act
        var result = DateTimeUtil.IsNowOrCountdownOnInterval(now, countdownTo, interval);

        // Assert
        Assert.False(result);
    }

    [Fact]
    public void IsOnInterval_CountdownReached_ShouldReturnTrue()
    {
        // Arrange
        var now = new DateTime(2024, 7, 18, 12, 30, 45);
        var countdownTo = new DateTime(2024, 7, 18, 12, 30, 45);
        var interval = TimeSpan.Zero; // No interval

        // Act
        var result = DateTimeUtil.IsNowOrCountdownOnInterval(now, countdownTo, interval);

        // Assert
        Assert.True(result);
    }

}