tests(calendar): Add calendar render tests (#3)

- updates calendar to support overriding the current day when rendering
- supports current culture when rendering
- renames Calendar to CalendarGenerator

.gitignore

@@ -5,4 +5,6 @@ riderModule.iml
 /_ReSharper.Caches/
 # Don't care about IDE specific things
 /.idea
-*.DotSettings.user
+*.DotSettings.user
+# Don't care about files created from the build script
+output/

Directory.Packages.props

@@ -0,0 +1,17 @@
+<Project>
+  <PropertyGroup>
+    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
+    <PackageVersion Include="System.IO.Packaging" Version="10.0.10" />
+    <PackageVersion Include="System.Security.Cryptography.Xml" Version="10.0.10" />
+    <PackageVersion Include="Microsoft.PowerShell.SDK" Version="7.6.4" />
+    <PackageVersion Include="PowerShellStandard.Library" Version="5.1.1" />
+    <PackageVersion Include="System.Management.Automation" Version="7.6.4" />
+    <PackageVersion Include="Cake.Frosting" Version="6.2.0" />
+    <PackageVersion Include="Cake.Powershell" Version="4.0.0" />
+    <PackageVersion Include="Verify.XunitV3" Version="31.27.0" />
+    <PackageVersion Include="xunit.v3" Version="3.2.2" />
+  </ItemGroup>
+</Project>

PowershellModule.slnx

@@ -0,0 +1,20 @@
+<Solution>
+  <Folder Name="/build/">
+    <Project Path="build/Build.csproj" />
+  </Folder>
+  <Folder Name="/harnesses/">
+    <Project Path="src/ModuleHarness/ModuleHarness.csproj" />
+    <Project Path="src/PowershellHarness/PowershellHarness.csproj" />
+  </Folder>
+  <Folder Name="/scripts/">
+    <File Path="build.ps1" />
+  </Folder>
+  <Folder Name="/solutionItems/">
+    <File Path="Directory.Packages.props" />
+  </Folder>
+  <Folder Name="/tests/">
+    <Project Path="tests/ModuleTests/ModuleTests.csproj" />
+  </Folder>
+  <Project Path="src/ModuleCore/ModuleCore.csproj" />
+  <Project Path="src/PowershellModule/PowershellModule.csproj" />
+</Solution>

build.ps1

@@ -0,0 +1,2 @@
+dotnet run --project build/Build.csproj -- $args
+exit $LASTEXITCODE;

build.sh

@@ -0,0 +1 @@
+dotnet run --project ./build/Build.csproj -- "$@"

build/Build.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <RunWorkingDirectory>$(MSBuildProjectDirectory)</RunWorkingDirectory>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="Cake.Frosting"/>
+    <PackageReference Include="Cake.Powershell"/>
+    <PackageReference Include="System.IO.Packaging" />
+    <PackageReference Include="System.Security.Cryptography.Xml" />
+  </ItemGroup>
+</Project>

build/Program.cs

@@ -0,0 +1,55 @@
+using Cake.Common;
+using Cake.Common.IO;
+using Cake.Common.IO.Paths;
+using Cake.Core;
+using Cake.Frosting;
+using Cake.Powershell;
+
+public static class Program
+{
+	public static int Main(string[] args)
+	{
+		return new CakeHost()
+			.UseContext<BuildContext>()
+			.Run(args);
+	}
+}
+
+public class BuildContext : FrostingContext
+{
+	/// <summary>
+	/// Base source directory
+	/// </summary>
+	public ConvertableDirectoryPath BaseSourceLocation { get; set; }
+
+	/// <summary>
+	/// Powershell module project folder
+	/// </summary>
+	public ConvertableDirectoryPath PowershellModuleProjectDirectory { get; set; }
+
+	/// <summary>
+	/// Powershell module csproj location
+	/// </summary>
+	public ConvertableFilePath PowershellModuleCsproj { get; set; }
+
+	/// <summary>
+	/// Output directory for built DLLs and powershell module manifest files
+	/// </summary>
+	public ConvertableDirectoryPath PowershellModuleOutputDir { get; set; }
+
+	/// <summary>
+	/// Path to powershell script that creates the module manifest files
+	/// </summary>
+	public ConvertableFilePath CreateModuleManifestScript { get; set; }
+
+	public BuildContext(ICakeContext context)
+		: base(context)
+	{
+		BaseSourceLocation = context.Directory("../src");
+		PowershellModuleProjectDirectory = BaseSourceLocation + context.Directory("PowershellModule");
+		PowershellModuleCsproj = PowershellModuleProjectDirectory + context.File("PowershellModule.csproj");
+		PowershellModuleOutputDir = context.Directory("../") + context.Directory("output") + context.Directory("PowershellModule");
+		var buildScriptDirectory = context.Directory("./Scripts");
+		CreateModuleManifestScript = buildScriptDirectory + context.File("CreateModuleManifest.ps1");
+	}
+}

build/Scripts/CreateModuleManifest.ps1

@@ -0,0 +1,24 @@
+param (
+    [string]$path,
+    [string]$guid,
+    [string]$author,
+    [string[]]$nestedModules,
+    [string]$rootModule,
+    [string[]]$cmdletsToExport,
+    [string]$manifestFileLocation
+)
+
+$manifestSplat = @{
+    Path = "$path"
+    GUID = "$guid"
+    Author = "$author"
+    NestedModules = @($nestedModules)
+    RootModule = "$rootModule"
+    CmdletsToExport = @($cmdletsToExport)
+    FunctionsToExport = @()
+    VariablesToExport = @()
+    AliasesToExport = @()
+}
+
+New-ModuleManifest @manifestSplat
+New-Item "$manifestFileLocation" -ItemType File

build/Tasks/BuildTask.cs

@@ -0,0 +1,36 @@
+using Cake.Common.Tools.DotNet;
+using Cake.Common.Tools.DotNet.Build;
+using Cake.Common.Tools.DotNet.MSBuild;
+using Cake.Core.Diagnostics;
+using Cake.Frosting;
+
+namespace Build.Tasks;
+
+[TaskName("Build")]
+[IsDependentOn(typeof(CleanTask))]
+[IsDependeeOf(typeof(CopyOutputTask))]
+public class BuildTask : FrostingTask<BuildContext>
+{
+	public override void Run(BuildContext context)
+	{
+		context.Log.Information($"Building: {context.PowershellModuleCsproj}");
+
+		var buildSettings = new DotNetBuildSettings()
+		{
+			MSBuildSettings = new DotNetMSBuildSettings()
+			{
+				VersionSuffix = "cake"
+			},
+			OutputDirectory = context.PowershellModuleOutputDir,
+			DiagnosticOutput = true
+		};
+
+		// /p:DebugSymbols=false
+		buildSettings.MSBuildSettings.Properties.Add("DebugSymbols", ["false"]);
+		// /p:DebugType=None
+		buildSettings.MSBuildSettings.Properties.Add("DebugType", ["None"]);
+
+		context.DotNetBuild(context.PowershellModuleCsproj, buildSettings);
+		base.Run(context);
+	}
+}

build/Tasks/CleanTask.cs

@@ -0,0 +1,23 @@
+using Cake.Common;
+using Cake.Common.Tools.DotNet;
+using Cake.Core.Diagnostics;
+using Cake.Frosting;
+
+namespace Build.Tasks;
+
+[TaskName("Clean")]
+public class CleanTask : FrostingTask<BuildContext>
+{
+	public override void Run(BuildContext context)
+	{
+		context.DotNetClean(context.PowershellModuleProjectDirectory);
+		
+		var outDir = context.FileSystem.GetDirectory(context.PowershellModuleOutputDir);
+		if (outDir.Exists)
+		{
+			outDir.Delete(true);
+		}
+
+		base.Run(context);
+	}
+}

build/Tasks/CopyOutputTask.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Linq;
+using Cake.Core.Diagnostics;
+using Cake.Core.IO;
+using Cake.Frosting;
+using Cake.Powershell;
+
+namespace Build.Tasks;
+
+[TaskName("CopyOutput")]
+public class CopyOutputTask : FrostingTask<BuildContext>
+{
+	public override void Run(BuildContext context)
+	{
+		var powershellModuleName = "PowershellModule";
+		var scriptParams = new
+		{
+			Path = $"{context.PowershellModuleOutputDir}/{powershellModuleName}.psd1",
+			Guid = Guid.Parse("5cdf4635-edb0-428c-8d9b-92d0bcd47443"),
+			Author = "Me",
+			NestedModules = new[] { $"{powershellModuleName}.dll" },
+			RootModule = $"{powershellModuleName}.psm1",
+			CmdletsToExport = new[] { "Get-Calendar" },
+			ManifestFileLocation = $"{context.PowershellModuleOutputDir}/{powershellModuleName}.psm1"
+		};
+		
+		var psSettings = new PowershellSettings()
+		{
+			Arguments = new ProcessArgumentBuilder(),
+		};
+
+		// This feels a bit ugly/redundant seeing as I've defined the scriptParams above, but I'm leaving it as is
+		// until I want to come back and clean this up properly
+		psSettings.Arguments.Append("path", ToPowershellSafeString(scriptParams.Path));
+		psSettings.Arguments.Append("guid", ToPowershellSafeString(scriptParams.Guid.ToString()));
+		psSettings.Arguments.Append("author", ToPowershellSafeString(scriptParams.Author));
+		psSettings.Arguments.Append("nestedModules", $"@({string.Join(",", scriptParams.NestedModules.Select(ToPowershellSafeString))})");
+		psSettings.Arguments.Append("rootModule", ToPowershellSafeString(scriptParams.RootModule));
+		psSettings.Arguments.Append("cmdletsToExport", $"@({string.Join(",", scriptParams.CmdletsToExport.Select(ToPowershellSafeString))})");
+		psSettings.Arguments.Append("manifestFileLocation", ToPowershellSafeString(scriptParams.ManifestFileLocation));
+
+		context.StartPowershellFile(context.CreateModuleManifestScript, psSettings);
+		context.Log.Information($"Module output to: {context.PowershellModuleOutputDir.Path.MakeAbsolute(context.Environment)}");
+
+		base.Run(context);
+	}
+
+	private static string ToPowershellSafeString(string unescapedString) => $"'{unescapedString}'";
+}

build/Tasks/DefaultTask.cs

@@ -0,0 +1,16 @@
+using Cake.Core;
+using Cake.Core.Diagnostics;
+using Cake.Frosting;
+
+namespace Build.Tasks;
+
+// Consider this the "entry" point for builds, task order is defined by a chain of IsDependentOn
+[TaskName("Default")]
+[IsDependentOn(typeof(CopyOutputTask))]
+public class DefaultTask : FrostingTask
+{
+	public override void Run(ICakeContext context)
+	{
+		base.Run(context);
+	}
+}

src/ModuleCore/Calendar/CalendarGenerator.cs

@@ -0,0 +1,261 @@
+using System.Globalization;
+using System.Text;
+
+namespace ModuleCore.Calendar;
+
+public sealed class CalendarGenerator
+{
+	public const string DefaultMarkedOffSymbol = "x";
+	public const DayOfWeek DefaultStartOfWeek = DayOfWeek.Monday;
+
+	private readonly string _markedOffSymbol;
+	private readonly DayOfWeek _startOfWeek;
+
+	/// <summary>
+	/// Holds configured day abbreviations, based on <see cref="CultureInfo"/>.
+	/// <para>
+	///	Using english as the culture: Sunday = Sun, Monday = Mon and so on. This lookup also starts with
+	/// Sunday as the first day to match the <see cref="DayOfWeek"/> enum starting with Sunday.
+	/// </para>
+	/// </summary>
+	private readonly List<string> _daysOfWeekLookup;
+
+	/// <summary>
+	/// Used to work out how to pad columns for each day, based on the longest abbreviated day
+	/// </summary>
+	private readonly int _dayWidth;
+
+	private readonly CultureInfo _cultureInfo;
+
+	private readonly string _rolloverDaySymbol = "";
+
+	public CalendarGenerator(string? markedDaySymbol = null, DayOfWeek? startOfWeek = null)
+	{
+		_markedOffSymbol = markedDaySymbol ?? DefaultMarkedOffSymbol;
+		_startOfWeek = startOfWeek ?? DefaultStartOfWeek;
+
+		// Generate localised day of week lookup table
+		_daysOfWeekLookup = new List<string>(7);
+		_dayWidth = _markedOffSymbol.Length;
+		_cultureInfo = CultureInfo.CurrentCulture;
+		for (var i = 0; i < 7; i++)
+		{
+			var localisedDayAbbreviation = _cultureInfo.DateTimeFormat.GetAbbreviatedDayName((DayOfWeek)i);
+
+			// For unicode languages (such as Japanese and Chinese), the length of a day will be reported as 1,
+			// but will display in a way that makes them look short or offset.
+			// eg:
+			// ┌───────────────────────────┐
+			// │             7月            │
+			// ├───┬───┬───┬───┬───┬───┬───┤
+			// │ 月 │ 火 │ 水 │ 木 │ 金 │ 土 │ 日 │
+			// ├───┴───┴───┴───┴───┴───┴───┤
+			// There's not really an easy fix I know of (yet) to resolve this (and I'm not really too bothered by it yet)
+			// so unfortunately it has to stay as a known bug as is currently
+			if (localisedDayAbbreviation.Length > _dayWidth)
+			{
+				_dayWidth = localisedDayAbbreviation.Length;
+			}
+
+			_daysOfWeekLookup.Add(localisedDayAbbreviation);
+		}
+
+		// Increase the width by 2 to include a space on either side
+		_dayWidth += 2;
+	}
+
+	/// <summary>
+	/// Renders the configured calendar for the given datetime
+	/// </summary>
+	/// <param name="month"></param>
+	/// <param name="todayOverride">Defaults to <see cref="DateTime.Now"/>, used to display elapsed days</param>
+	/// <returns></returns>
+	public string Render(DateTime month, DateTime? todayOverride = null)
+	{
+		var sb = new StringBuilder();
+		// Generate the header for the month/days of week
+		GenerateHeader(sb, month);
+
+		var calendarForMonth = GenerateCalendarForMonth(month, _markedOffSymbol, _startOfWeek, _rolloverDaySymbol, todayOverride ?? DateTime.Now);
+
+		for (var i = 0; i < calendarForMonth.WeeksInMonth; i++)
+		{
+			sb.Append("│");
+			for (var j = 0; j < 7; j++)
+			{
+				var index = j + i * 7;
+				// We align days to the right of their box, 1 off from the border.
+				// Sure I could center them, but honestly this is better to read.
+				sb.Append(calendarForMonth.Calendar[index].PadLeft(_dayWidth - 1));
+				sb.Append(" │");
+			}
+
+			sb.AppendLine();
+		}
+
+		// Cap the calendar off
+		GenerateSpacer(sb, "└", "─", "┴", "┘", true);
+
+		return sb.ToString();
+	}
+
+	private void GenerateHeader(StringBuilder sb, DateTime month)
+	{
+		// Top border for the calendar, with padder and seperator the same as there's no columns immediately
+		// under it
+		GenerateSpacer(sb, "┌", "─", "─", "┐");
+
+		var monthString = month.ToString("MMMM yyyy", _cultureInfo);
+		// total width of the calendar is width of the localised day calculated in the constructor, plus 7 extra
+		// to account for separators for each day.
+		// It shouldn't need to be said that the 7 here stands for days in a week
+		var calendarWidth = _dayWidth * 7 + 7;
+		// Calculate the offsets for 
+		var offsets = (
+			left: Math.Floor(calendarWidth / 2.0 + monthString.Length / 2.0),
+			right: Math.Ceiling(calendarWidth / 2.0 - monthString.Length / 2.0)
+		);
+
+		sb.Append("│")
+			.Append(monthString.PadLeft((int)offsets.left))
+			.AppendLine("│".PadLeft((int)offsets.right));
+
+		// Top border for the week
+		GenerateSpacer(sb, "├", "─", "┬", "┤");
+
+		// Work out the week display based on start of week
+		var d = 0;
+		do
+		{
+			// Index into the day of week, wrapping if needed from the configured start of the week.
+			// The DayOfWeek enum starts with Sunday, so by default the start of the week is 0,
+			// But most calendars visually start with Monday as the start of the week which is our default start
+			// of week.
+			// We also pad the string to the width of the day (minus 2 for spaces either side of the day), if
+			// the marked day symbol is a long string.
+			// Why did I decide to support arbitrary length marked days? Why not?
+			sb.Append($"│ {_daysOfWeekLookup[(d + (int)_startOfWeek) % 7].PadLeft(_dayWidth - 2)} ");
+			d++;
+		} while (d < 7);
+
+		// End the week block
+		sb.AppendLine("│");
+		// bottom border
+		GenerateSpacer(sb, "├", "─", "┼", "┤");
+	}
+
+	private void GenerateSpacer(StringBuilder sb, string leftCap, string padder, string seperator, string rightCap, bool noNewLine = false)
+	{
+		sb.Append(leftCap);
+		for (var i = 0; i < 7; i++)
+		{
+			for (var j = 0; j < _dayWidth; j++)
+			{
+				sb.Append(padder);
+			}
+
+			if (i < 6)
+			{
+				sb.Append(seperator);
+			}
+		}
+
+		if (noNewLine)
+		{
+			sb.Append(rightCap);
+		}
+		else
+		{
+			sb.AppendLine(rightCap);
+		}
+	}
+
+	private MonthCalendar GenerateCalendarForMonth(DateTime month, string markedOffSymbol, DayOfWeek calendarStartOfWeek, string rolloverDaySymbol, DateTime today)
+	{
+		// TODO: use startOfWeek to offset the start of the calendar later
+		// TODO: I think I meant the calendar name header?
+
+		// Reset the month to the start
+		var startOfMonth = new DateTime(month.Year, month.Month, 1);
+		// If the visual start of the month is before the actual start day of the month, we need to visually shift the
+		// calendar "back" a week, and pad appropriately.
+		// Eg, if the start of the month is Sunday, but our visual start of the week is a Monday, then we need to
+		// make a new week to display Monday as the start, and then pad blank days to Sunday.
+		// This could probably be calculated better to avoid annoying to read logic but I'm drunk at this moment so the
+		// brain ain't there.
+		// For what its worth, I wasn't drunk for the rest of the code in this file, as hard as that is to believe!
+		var daysToPadToStartMonth = startOfMonth.DayOfWeek >= calendarStartOfWeek
+			? startOfMonth.DayOfWeek - calendarStartOfWeek
+			: 7 - (calendarStartOfWeek - startOfMonth.DayOfWeek);
+
+		var daysInMonth = DateTime.DaysInMonth(month.Year, month.Month);
+		// TODO: a lot of this could probably be simplified by simply taking the start day of the week, and then
+		//       based on where it would be in the first week, work out if the month is 4, 5 or 6 weeks from that.
+		//       all this needs is a pre-calculated table and that's it.
+		//       Weeks have 7 days so there's only a fixed permutation of weeks based on the day of the week a month
+		//       starts on, and months have anywhere from 28 to 31 days
+		// Increase the days by the previous months
+		var paddedDaysInMonth = daysInMonth + daysToPadToStartMonth;
+		// How many days to add to the end to make the absolute number of days (including any
+		// days that would visually roll over on a calendar)
+		// eg, if there are 2 "roll over" days from the previous month and this month has 31 days,
+		// Work out how many days we have left from 7, then get the _final_ number of days to make it a multiple
+		// _of_ 7.
+		// So this results in (33%7) == 5 - 7 == 2 + 33 == 35 % 7 == 0 which means we have a "complete" month
+		// including next month roll over.
+		// Visually we won't be showing those roll over days but it makes things easier if I decide to later.
+		// If the days in the month plus padded days is already a multiple of 7, we don't need to add any more days.
+		var daysToPadToEndMonth = paddedDaysInMonth % 7 != 0
+			? 7 - paddedDaysInMonth % 7
+			: 0;
+		paddedDaysInMonth += daysToPadToEndMonth;
+		// Round to the nearest week after padding for the previous months days.
+		// Naively allowing a loss of precision via int division because the paddedDaysInMonth should always
+		// be a multiple of 7.
+		// "should always" is going to be found not as true later
+		var weeksInMonth = paddedDaysInMonth / 7;
+
+		var cal = new List<string>();
+		for (var i = 0; i < daysToPadToStartMonth; i++)
+		{
+			cal.Add(rolloverDaySymbol);
+		}
+
+		// If we're in the same year and month, any days already elapsed should be marked off,
+		// otherwise we display all days.
+		// If the DateTime we're rendering is in the past we render all days as marked off
+		// TODO: maybe don't do that and display the calendar differently
+		var hideElapsedDays = today.Year == month.Year && today.Month == month.Month;
+
+		for (var i = 1; i < daysInMonth + 1; i++)
+		{
+			// if we're marking off elapsed days and we're not today or ahead, 'mark' it off
+			if (hideElapsedDays && i < today.Day)
+			{
+				cal.Add(markedOffSymbol);
+			}
+			else
+			{
+				cal.Add($"{i}");
+			}
+		}
+
+		// pad the rollover days at the end of the calendar
+		for (var i = 0; i < daysToPadToEndMonth; i++)
+		{
+			cal.Add(rolloverDaySymbol);
+		}
+
+		return new MonthCalendar
+		{
+			Calendar = cal,
+			WeeksInMonth = weeksInMonth
+		};
+	}
+}
+
+public class MonthCalendar
+{
+	public List<string> Calendar { get; set; } = [];
+	public int WeeksInMonth { get; set; }
+}

src/ModuleCore/Directory.Build.props

@@ -0,0 +1,6 @@
+<Project>
+    <PropertyGroup>
+        <VersionPrefix>0.0.0</VersionPrefix>
+        <VersionSuffix>dev</VersionSuffix>
+    </PropertyGroup>
+</Project>

src/ModuleCore/ModuleCore.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <LangVersion>latestmajor</LangVersion>
+    </PropertyGroup>
+
+</Project>

src/ModuleHarness/ModuleHarness.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <LangVersion>latestmajor</LangVersion>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\ModuleCore\ModuleCore.csproj" />
+    </ItemGroup>
+
+</Project>

src/ModuleHarness/Program.cs

@@ -0,0 +1,20 @@
+using System.Text;
+using ModuleCore.Calendar;
+
+namespace ModuleHarness;
+
+class Program
+{
+	static void Main(string[] args)
+	{
+		Console.OutputEncoding = Encoding.Unicode;
+		var a = new CalendarGenerator();
+		var lastMonth = a.Render(DateTime.Now.AddMonths(-1));
+		var now = a.Render(DateTime.Now);
+		var august = a.Render(DateTime.Now.AddMonths(1));
+
+		Console.Write(lastMonth);
+		Console.Write(now);
+		Console.Write(august);
+	}
+}

src/PowershellHarness/CustomHost.cs

@@ -0,0 +1,216 @@
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Management.Automation;
+using System.Management.Automation.Host;
+using System.Security;
+using System.Text;
+
+namespace PowershellHarness;
+
+// A whole bunch of empty implementations just so cmdlets have access to anything within Host.Ui (and probably any cmdlets
+// that prompt for information later)
+// https://github.com/leechristensen/OffensivePowerShellTasking/blob/master/OffensivePowerShellTasking/CustomPSHost.cs#L13
+public class CustomHost : PSHost
+{
+	public override string Name => "Custom Host";
+	public override Version Version { get; } = new Version(0, 0, 0, 0);
+	public override Guid InstanceId { get; } = Guid.NewGuid();
+
+	private CustomUiHost _ui = new CustomUiHost();
+	public override CustomUiHost UI => _ui;
+
+	public override CultureInfo CurrentCulture { get; } = CultureInfo.CurrentCulture;
+	public override CultureInfo CurrentUICulture { get; } = CultureInfo.CurrentUICulture;
+
+	public CustomHost(int width, int height = 100)
+	{
+		_ui.RawUI.WindowSize = new() { Width = width, Height = height };
+	}
+
+	public override void EnterNestedPrompt()
+	{
+		throw new NotImplementedException("EnterNestedPrompt is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override void ExitNestedPrompt()
+	{
+		throw new NotImplementedException("ExitNestedPrompt is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override void NotifyBeginApplication()
+	{
+	}
+
+	public override void NotifyEndApplication()
+	{
+	}
+
+	public override void SetShouldExit(int exitCode)
+	{
+	}
+}
+
+// https://github.com/leechristensen/OffensivePowerShellTasking/blob/d1b498d874948f41e6dc053204c511fa6fc11c9c/OffensivePowerShellTasking/CustomPSHostUserInterface.cs#L8
+public class CustomUiHost : PSHostUserInterface
+{
+	// The only stuff that really matters to expose a host for any cmdlets
+	private readonly CustomRawUiHost _rawUI = new CustomRawUiHost();
+	public override CustomRawUiHost RawUI => _rawUI;
+
+	// Replace StringBuilder with whatever your preferred output method is (e.g. a socket or a named pipe)
+	public StringBuilder output { get; set; }
+
+	public CustomUiHost()
+	{
+		output = new StringBuilder();
+	}
+
+	public CustomUiHost(ref StringBuilder sb)
+	{
+		output = sb;
+	}
+
+	public override void Write(ConsoleColor foregroundColor, ConsoleColor backgroundColor, string value)
+	{
+		//output.Append("!").Append(value);
+	}
+
+	public override void WriteLine()
+	{
+		//output.Append("!").Append("\n");
+	}
+
+	public override void WriteLine(ConsoleColor foregroundColor, ConsoleColor backgroundColor, string value)
+	{
+		//output.Append("!").Append(value + "\n");
+	}
+
+	public override void Write(string value)
+	{
+		//output.Append("!").Append(value);
+	}
+
+	public override void WriteDebugLine(string message)
+	{
+		//output.Append("!").AppendLine("DEBUG: " + message);
+	}
+
+	public override void WriteErrorLine(string value)
+	{
+		//output.Append("!").AppendLine("ERROR: " + value);
+	}
+
+	public override void WriteLine(string value)
+	{
+		//output.Append("!").AppendLine(value);
+	}
+
+	public override void WriteVerboseLine(string message)
+	{
+		//output.Append("!").AppendLine("VERBOSE: " + message);
+	}
+
+	public override void WriteWarningLine(string message)
+	{
+		//output.Append("!").AppendLine("WARNING: " + message);
+	}
+
+	public override void WriteProgress(long sourceId, ProgressRecord record)
+	{
+	}
+
+	public string Output => output.ToString();
+
+	public override Dictionary<string, PSObject> Prompt(string caption, string message, System.Collections.ObjectModel.Collection<FieldDescription> descriptions)
+	{
+		throw new NotImplementedException("Prompt is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override int PromptForChoice(string caption, string message, System.Collections.ObjectModel.Collection<ChoiceDescription> choices, int defaultChoice)
+	{
+		throw new NotImplementedException("PromptForChoice is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override PSCredential PromptForCredential(string caption, string message, string userName, string targetName, PSCredentialTypes allowedCredentialTypes, PSCredentialUIOptions options)
+	{
+		throw new NotImplementedException("PromptForCredential1 is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override PSCredential PromptForCredential(string caption, string message, string userName, string targetName)
+	{
+		throw new NotImplementedException("PromptForCredential2 is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override string ReadLine()
+	{
+		throw new NotImplementedException("ReadLine is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override SecureString ReadLineAsSecureString()
+	{
+		throw new NotImplementedException("ReadLineAsSecureString is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+}
+
+// https://github.com/leechristensen/OffensivePowerShellTasking/blob/master/OffensivePowerShellTasking/CustomPSRHostRawUserInterface.cs#L8
+public class CustomRawUiHost : PSHostRawUserInterface
+{
+	public override ConsoleColor BackgroundColor { get; set; } = ConsoleColor.Black;
+
+	public override Size BufferSize { get; set; } = new Size { Width = 100, Height = 1000 };
+
+	public override Coordinates CursorPosition { get; set; } = new Coordinates { X = 0, Y = 0 };
+
+	public override int CursorSize { get; set; } = 1;
+
+	public override void FlushInputBuffer()
+	{
+		throw new NotImplementedException("FlushInputBuffer is not implemented.");
+	}
+
+	public override ConsoleColor ForegroundColor { get; set; } = ConsoleColor.White;
+
+	public override BufferCell[,] GetBufferContents(Rectangle rectangle)
+	{
+		throw new NotImplementedException("GetBufferContents is not implemented.");
+	}
+
+	public override bool KeyAvailable
+	{
+		get { throw new NotImplementedException("KeyAvailable is not implemented."); }
+	}
+
+	public override Size MaxPhysicalWindowSize { get; } = new Size
+	{
+		Width = int.MaxValue,
+		Height = int.MaxValue
+	};
+
+	public override Size MaxWindowSize { get; } = new Size { Width = 100, Height = 100 };
+
+	public override KeyInfo ReadKey(ReadKeyOptions options)
+	{
+		throw new NotImplementedException("ReadKey is not implemented.  The script is asking for input, which is a problem since there's no console.  Make sure the script can execute without prompting the user for input.");
+	}
+
+	public override void ScrollBufferContents(Rectangle source, Coordinates destination, Rectangle clip, BufferCell fill)
+	{
+		throw new NotImplementedException("ScrollBufferContents is not implemented");
+	}
+
+	public override void SetBufferContents(Rectangle rectangle, BufferCell fill)
+	{
+		throw new NotImplementedException("SetBufferContents is not implemented.");
+	}
+
+	public override void SetBufferContents(Coordinates origin, BufferCell[,] contents)
+	{
+		throw new NotImplementedException("SetBufferContents is not implemented");
+	}
+
+	public override Coordinates WindowPosition { get; set; } = new Coordinates { X = 0, Y = 0 };
+
+	public override Size WindowSize { get; set; } = new Size { Width = 120, Height = 100 };
+
+	public override string WindowTitle { get; set; } = "";
+}

src/PowershellHarness/PowershellHarness.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="Microsoft.PowerShell.SDK" />
+      <PackageReference Include="System.Security.Cryptography.Xml" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\PowershellModule\PowershellModule.csproj" />
+    </ItemGroup>
+
+</Project>

src/PowershellHarness/Program.cs

@@ -0,0 +1,145 @@
+using System.Management.Automation;
+using System.Management.Automation.Runspaces;
+using System.Text;
+using PowershellModule.Calendar;
+
+namespace PowershellHarness;
+
+// https://github.com/FuseCP/FuseCP/blob/278a19dc06949600f25a1b4ed74d0419a8fa3fc2/FuseCP/Sources/FuseCP.Providers.HostedSolution.SfB2015/SfBBase.cs#L224
+// some useful code in here tbh
+class Program
+{
+	static void Main(string[] args)
+	{
+		// I've gotta work out how to get the rider terminal to act closer to powershell because .PadLeft in powershell
+		// will correctly output lines when output with WriteOutput, but the Jetbrains debug worker (or whatever
+		// it is that rider spawns), has none of that and operates in its own world.
+		// Which is fine if you never want new lines.
+		// Ideally you'd just launch pwsh.exe and attach to that, but _that_ has its own issues as well.
+		// The new line issue might be related to how I've set up the host seeing as I just did a bunch of copy paste shit
+		// from something I found on github to get it across the line so I could debug it.
+		// I'll eventually revisit those hosts and rewrite them properly once I start adding more commands, and if I care.
+		// Threads & variables has all the visuals I need after all.
+#if DEBUG
+		if (!System.Diagnostics.Debugger.IsAttached)
+		{
+			Console.BackgroundColor = ConsoleColor.Yellow;
+			Console.WriteLine(CenterText("Running without a debugger attached may result in lines not being output correctly"));
+			Console.ResetColor();
+		}
+#endif
+		Console.WriteLine(CenterText(" PowerShell Debug Harness "));
+		Console.WriteLine($"Reported console window size: {Console.WindowWidth}x{Console.WindowHeight}");
+		Console.WriteLine($"Reported console buffer size: {Console.BufferWidth}x{Console.BufferHeight}");
+		Console.WriteLine(CenterText(" WIDTH ", '-'));
+
+		var host = new CustomHost(Console.WindowWidth);
+		var runspace = InitialisePowershellHost(host);
+
+		// InvokeCommand(runspace, GetCalendarCommand.FullName);
+
+		foreach (var day in Enum.GetValues<DayOfWeek>())
+		{
+			InvokeCommand(runspace, GetCalendarCommand.FullName, [
+				CreateCommand(nameof(GetCalendarCommand.MarkedDaySymbol), "faker"),
+				CreateCommand(nameof(GetCalendarCommand.StartOfWeek), day.ToString()),
+				CreateCommand(nameof(GetCalendarCommand.Date), "22/6/26"),
+				// CreateCommand(nameof(GetCalendarCommand.AlignRight))
+			]);
+		}
+
+		// InvokeCommand(runspace, GetCalendarCommand.FullName, [
+		// 	new CommandParameter(nameof(GetCalendarCommand.MarkedDaySymbol), "🤫"),
+		// 	new CommandParameter(nameof(GetCalendarCommand.StartOfWeek), DayOfWeek.Saturday)
+		// ]);
+		// InvokeCommand(runspace, GetCalendarCommand.FullName, [new CommandParameter(nameof(GetCalendarCommand.StartOfWeek), "Sunday")]);
+	}
+
+	private static CommandParameter CreateCommand(string name, string? argument = null)
+	{
+		if (argument is not null)
+		{
+			return new CommandParameter(name, argument);
+		}
+
+		return new CommandParameter(name);
+	}
+
+	static string CenterText(string text, char paddingChar = ' ')
+	{
+		return text.PadLeft((Console.WindowWidth + text.Length) / 2, paddingChar).PadRight(Console.WindowWidth, paddingChar);
+	}
+
+	/// <summary>
+	/// Initialises a PowerShell session and returns an open Runspace
+	/// </summary>
+	/// <param name="host"></param>
+	/// <returns></returns>
+	static Runspace InitialisePowershellHost(CustomHost host)
+	{
+		// Create the initial session state for the host. Yes, that 2 on the end does indicate that the underlying
+		// implementation for this is C++
+		// Welcome to the lands of fuck all documentation and figuring shit out from an increasingly shit internet
+		// where finding non-slop answers gets harder by the day as people close sources of information to prevent
+		// scraping. Fuck every single person involved modern AI.
+		// It wasn't much better finding documentation about the System.Management.* namespace before that, but it's
+		// definitely a lot worse because of it
+		var initialSessionState = InitialSessionState.CreateDefault2();
+
+
+		// No idea what the helpFileName should be. As is common with _a lot_ of the System.Management.* namespace,
+		// fuck all is actually documented with comments, or documented at all!
+		// From https://learn.microsoft.com/en-us/powershell/scripting/developer/hosting/creating-a-constrained-runspace?view=powershell-7.6
+		// (which yes, this section _is_ under a legacy category!), it's perfectly fine to leave it as null.
+		// We also don't really care as we're just doing this so we can test commands without having to deal with Rider
+		// and it's quirks around runnning a powershell terminal and attaching to it. Yeah it technically works, but
+		// it's way too common to end up with Rider refusing to build correctly or ensure the right dll is used for the module
+		var getCalendarCommand = new SessionStateCmdletEntry(GetCalendarCommand.FullName, typeof(GetCalendarCommand), null);
+		initialSessionState.Commands.Add(getCalendarCommand);
+
+		// Create a runspace from the state, open and return it
+		var runspace = RunspaceFactory.CreateRunspace(host, initialSessionState);
+
+		// A runspace is technically disposable, but we're not reimplementing a full host and we won't be doing anything
+		// that would require a fresh runspace multiple times over (yet), so we can just treat the lifetime of the
+		// disposable as application lifetime
+		runspace.Open();
+
+		return runspace;
+	}
+
+	static void InvokeCommand(Runspace runspace, string command, IEnumerable<CommandParameter>? parameters = null)
+	{
+		// Not too sure on the difference of runspace vs PowerShell here. Doesn't seem to make a difference either way
+		// and this is just a debug harness so it doesn't really matter for now
+		using var pipeline = runspace.CreatePipeline();
+		// using var powershell = PowerShell.Create(runspace);
+
+		var cmd = new Command(command);
+		if (parameters is not null)
+		{
+			foreach (var commandParameter in parameters)
+			{
+				cmd.Parameters.Add(commandParameter);
+			}
+		}
+
+		pipeline.Commands.Add(cmd);
+		// powershell.Commands.AddCommand(cmd);
+
+		try
+		{
+			var results = pipeline.Invoke();
+			// var results = powershell.Invoke();
+			foreach (var result in results)
+			{
+				Console.Write(result);
+			}
+		}
+		catch (Exception ex)
+		{
+			Console.Error.WriteLine($"Unable to execute command {command}");
+			Console.Error.WriteLine(ex.GetBaseException().Message);
+		}
+	}
+}

src/PowershellModule/Calendar/GetCalendarCommand.cs

@@ -0,0 +1,174 @@
+using System;
+using System.Globalization;
+using System.Management.Automation;
+using ModuleCore.Calendar;
+
+namespace PowershellModule.Calendar
+{
+	[Cmdlet(VerbsCommon.Get, Noun)]
+	public class GetCalendarCommand : PSCmdlet
+	{
+#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
+		[Parameter(
+			Mandatory = false,
+			Position = 0)]
+		public string Date { get; set; }
+
+		[Parameter(
+			Mandatory = false,
+			Position = 1)]
+		public string MarkedDaySymbol { get; set; }
+
+		[Parameter(
+			Mandatory = false,
+			Position = 2)]
+		[ValidateSet("Sunday",
+			"Monday",
+			"Tuesday",
+			"Wednesday",
+			"Thursday",
+			"Friday",
+			"Saturday")]
+		// pass a type in to get dynamic types
+		// NOTE: the generator gets called for _each_ character input, so ensure the values are idempotent for every
+		// keydown (and fast), or cached
+		// [ValidateSet(typeof(StartDayOfWeekGenerator))]
+		public string StartOfWeek { get; set; }
+
+		[Parameter(
+			Mandatory = false,
+			Position = 3)]
+		public SwitchParameter AlignRight { get; set; }
+
+#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring as nullable.
+
+		// Guaranteed to be initialised in BeginProcessing. If it's not, something is cooked in some other way
+		private CalendarGenerator _calendar = null!;
+		private const string Noun = "Calendar";
+		public const string FullName = $"{VerbsCommon.Get}-{Noun}";
+
+		private DateTime _dateToRender = DateTime.Now;
+		private int _leftPadding;
+
+		protected override void BeginProcessing()
+		{
+			// This is the first point in script execution where we'll have parameters populated
+			_calendar = new(
+				MarkedDaySymbol,
+				DayOfWeekFromString(StartOfWeek)
+			);
+
+			if (!string.IsNullOrWhiteSpace(Date))
+			{
+				_dateToRender = DateTime.ParseExact(Date, CultureInfo.CurrentCulture.DateTimeFormat.GetAllDateTimePatterns(), null);
+			}
+
+			if (AlignRight)
+			{
+				_leftPadding = Host.UI.RawUI.WindowSize.Width;
+			}
+		}
+
+		/// <summary>
+		/// Returns a <see cref="DayOfWeek"/> from a string.
+		/// <para>
+		///	Defaults to the calendars default start of week on null or invalid values.
+		/// </para>
+		/// </summary>
+		/// <param name="dayOfWeek"></param>
+		/// <returns></returns>
+		private static DayOfWeek DayOfWeekFromString(string? dayOfWeek)
+		{
+			if (dayOfWeek is null)
+			{
+				return CalendarGenerator.DefaultStartOfWeek;
+			}
+
+			return dayOfWeek.ToLowerInvariant() switch
+			{
+				"sunday" => DayOfWeek.Sunday,
+				"monday" => DayOfWeek.Monday,
+				"tuesday" => DayOfWeek.Tuesday,
+				"wednesday" => DayOfWeek.Wednesday,
+				"thursday" => DayOfWeek.Thursday,
+				"friday" => DayOfWeek.Friday,
+				"saturday" => DayOfWeek.Saturday,
+				_ => CalendarGenerator.DefaultStartOfWeek
+			};
+		}
+
+		protected override void ProcessRecord()
+		{
+			var calendar = _calendar.Render(_dateToRender);
+
+			// From _very_ basic testing, string split allocates the same as making a span and iterating over it.
+			// I'm assuming this is because a lot of the span code is what string.Split() does internally and the rest
+			// is trivially optimised out.
+			// Not too fussed currently but it's most likely because Pad methods also allocate a string, so they end up
+			// equivalent at the end
+			// OutputCalendarStringSplit(calendar);
+			OutputCalendar(calendar);
+
+			base.ProcessRecord();
+		}
+
+		private void OutputCalendarStringSplit(string calendar)
+		{
+			var splitCalendarLines = calendar.Split(Environment.NewLine);
+			foreach (var splitLines in splitCalendarLines)
+			{
+				// Have to output a newline character here
+				WriteObject(splitLines.PadLeft(_leftPadding));
+			}
+		}
+
+		private void OutputCalendar(string calendar)
+		{
+			// Work on a span - we avoid using string.Split() as this allocates on certain runtimes
+			var calendarSpan = calendar.AsSpan();
+			// Get the end of line for the calendar. We use Environment.NewLine as the calendar is built up using
+			// StringBuilder which uses Environment.NewLine for new lines so this should be consistent across operating systems
+			var firstNewlineIndex = calendarSpan.IndexOf(Environment.NewLine);
+			// Calculate how many lines the calendar is from how many new lines we have.
+			// Sure we could count the number of \r\n are present, but the last line might not end with
+			// a new line.
+			// Conveniently enough, int division works out in our favor here
+			var lines = calendarSpan.Length / firstNewlineIndex;
+
+			// We need to account for the size of the newline so we have an accurate length when outputting each line
+			// of the calendar below
+			var newLineLength = firstNewlineIndex + Environment.NewLine.Length;
+
+			for (int i = 0; i < lines; i++)
+			{
+				// The start of each calendar line offset starts at a position including the length of the newline,
+				// so in effect the start of the line is the length of the previous line output, plus however many
+				// characters the newline was that weren't output as we're taking control there
+				var startOfLine = i * newLineLength;
+				// End of the line is exclusive of any newline characters
+				var endOfLine = startOfLine + firstNewlineIndex;
+				var calendarLine = calendarSpan[startOfLine .. endOfLine];
+
+				WriteObject(calendarLine.ToString().PadLeft(_leftPadding));
+			}
+		}
+	}
+
+	// Was here to test dynamic day names but most people using the console will be using english command names
+	// so there's at least some assumption that they understand days of the week in english.
+	// It sucks but it remains at least consistent with the argument being in english as well.
+	// public class StartDayOfWeekGenerator : IValidateSetValuesGenerator
+	// {
+	// 	private string[] _cached { get; set; } = new string[7];
+	//
+	// 	public string[] GetValidValues()
+	// 	{
+	// 		if (_cached is null)
+	// 		{
+	// 			// _cached = Enumerable.Range(0, r.Next(3, 63)).Select(x => x.ToString()).ToArray();
+	// 		}
+	//
+	// 		return _cached;
+	// 	}
+	// }
+}

src/PowershellModule/Directory.Build.props

@@ -0,0 +1,6 @@
+<Project>
+    <PropertyGroup>
+        <VersionPrefix>0.0.0</VersionPrefix>
+        <VersionSuffix>dev</VersionSuffix>
+    </PropertyGroup>
+</Project>

src/PowershellModule/PowershellModule.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <AssemblyName>PowershellModule</AssemblyName>
+    <LangVersion>latestmajor</LangVersion>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="PowerShellStandard.Library" >
+      <PrivateAssets>All</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="System.Management.Automation" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ModuleCore\ModuleCore.csproj" />
+  </ItemGroup>  
+</Project>

src/PowershellModule/manifest.json

@@ -0,0 +1,5 @@
+{
+  "_TODO":[
+    "add manifest details here maybe idk"
+  ]
+}

tests/ModuleTests/Calendar/BasicRenderTest.cs

@@ -0,0 +1,48 @@
+using ModuleCore.Calendar;
+using ModuleTests.Calendar.TestData;
+using System.Globalization;
+
+namespace ModuleTests.Calendar;
+
+public class BasicRenderTest
+{
+	private static readonly VerifySettings Settings;
+
+	static BasicRenderTest()
+	{
+		Settings = new VerifySettings();
+		var testBaseDirectory = Path.Join(TestConstants.SnapshotFolderName, nameof(BasicRenderTest));
+
+		Settings.UseDirectory(testBaseDirectory);
+		Settings.DisableDiff();
+	}
+
+	[Theory]
+	[ClassData(typeof(CalendarTestDates))]
+	public Task BasicCalendarRender(DateTime month)
+	{
+		Settings.UseFileName($"{month:yyyy-MM-dd}");
+
+		var calendar = new CalendarGenerator();
+		// Render the calendar with the start of the month as the today date so no elapsed marks are shown
+		var renderedMonth = calendar.Render(month, new DateTime(month.Year, month.Month, 1));
+
+		return Verify(renderedMonth, Settings);
+	}
+
+	[Theory]
+	[ClassData(typeof(CultureCodeTestData))]
+	public Task CultureInfoCalendarRender(string cultureCode)
+	{
+		Settings.UseFileName($"{cultureCode}");
+
+		Thread.CurrentThread.CurrentCulture = new CultureInfo(cultureCode);
+
+		var month = new DateTime(2026, 8, 1);
+		var calendar = new CalendarGenerator();
+		// Render the calendar with the start of the month as the today date so no elapsed marks are shown
+		var renderedMonth = calendar.Render(month, new DateTime(month.Year, month.Month, 1));
+
+		return Verify(renderedMonth, Settings);
+	}
+}

tests/ModuleTests/Calendar/MarkedDayRenderTests.cs

@@ -0,0 +1,86 @@
+using System.Text;
+using ModuleCore.Calendar;
+
+namespace ModuleTests.Calendar;
+
+public class MarkedDayRenderTests
+{
+	private static readonly VerifySettings Settings;
+
+	static MarkedDayRenderTests()
+	{
+		Settings = new VerifySettings();
+		var testBaseDirectory = Path.Join(TestConstants.SnapshotFolderName, nameof(MarkedDayRenderTests));
+
+		Settings.UseDirectory(testBaseDirectory);
+		Settings.DisableDiff();
+	}
+
+	[Fact]
+	public Task DefaultMarkedDayRender()
+	{
+		Settings.UseFileName(nameof(DefaultMarkedDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		var calendar = new CalendarGenerator();
+		var renderedMonth = calendar.Render(date, date.AddDays(15));
+
+		return Verify(renderedMonth, Settings);
+	}
+
+	[Fact]
+	public Task SimpleMarkedDayRender()
+	{
+		Settings.UseFileName(nameof(SimpleMarkedDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		var calendar = new CalendarGenerator("|");
+		var renderedMonth = calendar.Render(date, date.AddDays(15));
+
+		return Verify(renderedMonth, Settings);
+	}
+
+	[Fact]
+	public Task LongMarkedDayRender()
+	{
+		Settings.UseFileName(nameof(LongMarkedDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		var calendar = new CalendarGenerator("passed");
+		var renderedMonth = calendar.Render(date, date.AddDays(15));
+
+		return Verify(renderedMonth, Settings);
+	}
+
+	[Fact]
+	public Task EmojiMarkedDayRender()
+	{
+		Settings.UseFileName(nameof(EmojiMarkedDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		var calendar = new CalendarGenerator("🤫");
+		var sb = new StringBuilder();
+		sb.AppendLine("Emojis will display incorrectly in text but output correctly in terminals with UTF-8 encoding.")
+			.AppendLine(calendar.Render(date, date.AddDays(15)));
+
+		return Verify(sb, Settings);
+	}
+
+	[Fact]
+	public Task DoubleWideMarkedDayRender()
+	{
+		Settings.UseFileName(nameof(DoubleWideMarkedDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		// Using an asian-character to have a test covering the unfortunate reality of character rendering of
+		// characters that are visually 1 character in width, but render as double width or some other cursed form.
+		// Written language was a mistake but trying to render it on computers alongside a different one
+		// is arguably worse.
+		var calendar = new CalendarGenerator("火");
+		var sb = new StringBuilder();
+		sb.AppendLine("Double-wide characters will display incorrectly but still tested until rendering can be improved")
+			.AppendLine(calendar.Render(date, date.AddDays(15)));
+
+		return Verify(sb, Settings);
+	}
+}

tests/ModuleTests/Calendar/StartDayOfWeekTests.cs

@@ -0,0 +1,35 @@
+using System.Text;
+using ModuleCore.Calendar;
+
+namespace ModuleTests.Calendar;
+
+public class StartDayOfWeekTests
+{
+	private static readonly VerifySettings Settings;
+
+	static StartDayOfWeekTests()
+	{
+		Settings = new VerifySettings();
+		var testBaseDirectory = Path.Join(TestConstants.SnapshotFolderName, nameof(StartDayOfWeekTests));
+
+		Settings.UseDirectory(testBaseDirectory);
+		Settings.DisableDiff();
+	}
+
+	[Fact]
+	public Task StartOfDayRender()
+	{
+		Settings.UseFileName(nameof(StartOfDayRender));
+
+		var date = new DateTime(2026, 8, 1);
+		var sb = new StringBuilder();
+		foreach (var dayOfWeek in Enum.GetValues<DayOfWeek>())
+		{
+			var calendar = new CalendarGenerator(startOfWeek: dayOfWeek);
+			sb.AppendLine($"Start Day: {dayOfWeek}");
+			sb.AppendLine(calendar.Render(date, date));
+		}
+
+		return Verify(sb, Settings);
+	}
+}

tests/ModuleTests/Calendar/TestData/CalendarTestDates.cs

@@ -0,0 +1,14 @@
+namespace ModuleTests.Calendar.TestData;
+
+public class CalendarTestDates : TestDataEnumerator<DateTime>
+{
+	public CalendarTestDates()
+	{
+		Data =
+		[
+			new DateTime(2026, 06, 01),
+			new DateTime(2026, 07, 01),
+			new DateTime(2026, 08, 01),
+		];
+	}
+}

tests/ModuleTests/Calendar/TestData/CultureCodeTestData.cs

@@ -0,0 +1,19 @@
+namespace ModuleTests.Calendar.TestData;
+
+public class CultureCodeTestData : TestDataEnumerator<string>
+{
+	public CultureCodeTestData()
+	{
+		Data =
+		[
+			"da-DK",
+			"en-AU",
+			"cs-CZ",
+			"es-PR",
+			"fr-LU",
+			"nl-NL",
+			// Will render unaligned due to the character encoding, here to catch if I fix this later
+			"te-IN"
+		];
+	}
+}

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/2026-06-01.verified.txt

@@ -0,0 +1,11 @@
+┌─────────────────────────────────────────┐
+│                June 2026                │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│   1 │   2 │   3 │   4 │   5 │   6 │   7 │
+│   8 │   9 │  10 │  11 │  12 │  13 │  14 │
+│  15 │  16 │  17 │  18 │  19 │  20 │  21 │
+│  22 │  23 │  24 │  25 │  26 │  27 │  28 │
+│  29 │  30 │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/2026-07-01.verified.txt

@@ -0,0 +1,11 @@
+┌─────────────────────────────────────────┐
+│                July 2026                │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │   1 │   2 │   3 │   4 │   5 │
+│   6 │   7 │   8 │   9 │  10 │  11 │  12 │
+│  13 │  14 │  15 │  16 │  17 │  18 │  19 │
+│  20 │  21 │  22 │  23 │  24 │  25 │  26 │
+│  27 │  28 │  29 │  30 │  31 │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/2026-08-01.verified.txt

@@ -0,0 +1,12 @@
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   1 │   2 │
+│   3 │   4 │   5 │   6 │   7 │   8 │   9 │
+│  10 │  11 │  12 │  13 │  14 │  15 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/cs-CZ.verified.txt

@@ -0,0 +1,12 @@
+┌──────────────────────────────────┐
+│            srpen 2026            │
+├────┬────┬────┬────┬────┬────┬────┤
+│ po │ út │ st │ čt │ pá │ so │ ne │
+├────┼────┼────┼────┼────┼────┼────┤
+│    │    │    │    │    │  1 │  2 │
+│  3 │  4 │  5 │  6 │  7 │  8 │  9 │
+│ 10 │ 11 │ 12 │ 13 │ 14 │ 15 │ 16 │
+│ 17 │ 18 │ 19 │ 20 │ 21 │ 22 │ 23 │
+│ 24 │ 25 │ 26 │ 27 │ 28 │ 29 │ 30 │
+│ 31 │    │    │    │    │    │    │
+└────┴────┴────┴────┴────┴────┴────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/da-DK.verified.txt

@@ -0,0 +1,12 @@
+┌─────────────────────────────────────────┐
+│               august 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ man │ tir │ ons │ tor │ fre │ lør │ søn │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   1 │   2 │
+│   3 │   4 │   5 │   6 │   7 │   8 │   9 │
+│  10 │  11 │  12 │  13 │  14 │  15 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/en-AU.verified.txt

@@ -0,0 +1,12 @@
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   1 │   2 │
+│   3 │   4 │   5 │   6 │   7 │   8 │   9 │
+│  10 │  11 │  12 │  13 │  14 │  15 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/es-PR.verified.txt

@@ -0,0 +1,12 @@
+┌────────────────────────────────────────────────┐
+│                   agosto 2026                  │
+├──────┬──────┬──────┬──────┬──────┬──────┬──────┤
+│ lun. │ mar. │ mié. │ jue. │ vie. │ sáb. │ dom. │
+├──────┼──────┼──────┼──────┼──────┼──────┼──────┤
+│      │      │      │      │      │    1 │    2 │
+│    3 │    4 │    5 │    6 │    7 │    8 │    9 │
+│   10 │   11 │   12 │   13 │   14 │   15 │   16 │
+│   17 │   18 │   19 │   20 │   21 │   22 │   23 │
+│   24 │   25 │   26 │   27 │   28 │   29 │   30 │
+│   31 │      │      │      │      │      │      │
+└──────┴──────┴──────┴──────┴──────┴──────┴──────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/fr-LU.verified.txt

@@ -0,0 +1,12 @@
+┌────────────────────────────────────────────────┐
+│                    août 2026                   │
+├──────┬──────┬──────┬──────┬──────┬──────┬──────┤
+│ lun. │ mar. │ mer. │ jeu. │ ven. │ sam. │ dim. │
+├──────┼──────┼──────┼──────┼──────┼──────┼──────┤
+│      │      │      │      │      │    1 │    2 │
+│    3 │    4 │    5 │    6 │    7 │    8 │    9 │
+│   10 │   11 │   12 │   13 │   14 │   15 │   16 │
+│   17 │   18 │   19 │   20 │   21 │   22 │   23 │
+│   24 │   25 │   26 │   27 │   28 │   29 │   30 │
+│   31 │      │      │      │      │      │      │
+└──────┴──────┴──────┴──────┴──────┴──────┴──────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/nl-NL.verified.txt

@@ -0,0 +1,12 @@
+┌──────────────────────────────────┐
+│           augustus 2026          │
+├────┬────┬────┬────┬────┬────┬────┤
+│ ma │ di │ wo │ do │ vr │ za │ zo │
+├────┼────┼────┼────┼────┼────┼────┤
+│    │    │    │    │    │  1 │  2 │
+│  3 │  4 │  5 │  6 │  7 │  8 │  9 │
+│ 10 │ 11 │ 12 │ 13 │ 14 │ 15 │ 16 │
+│ 17 │ 18 │ 19 │ 20 │ 21 │ 22 │ 23 │
+│ 24 │ 25 │ 26 │ 27 │ 28 │ 29 │ 30 │
+│ 31 │    │    │    │    │    │    │
+└────┴────┴────┴────┴────┴────┴────┘

tests/ModuleTests/Calendar/snapshots/BasicRenderTest/te-IN.verified.txt

@@ -0,0 +1,12 @@
+┌───────────────────────────────────────────────────────┐
+│                      ఆగస్టు 2026                      │
+├───────┬───────┬───────┬───────┬───────┬───────┬───────┤
+│   సోమ │  మంగళ │   బుధ │  గురు │ శుక్ర │   శని │   ఆది │
+├───────┼───────┼───────┼───────┼───────┼───────┼───────┤
+│       │       │       │       │       │     1 │     2 │
+│     3 │     4 │     5 │     6 │     7 │     8 │     9 │
+│    10 │    11 │    12 │    13 │    14 │    15 │    16 │
+│    17 │    18 │    19 │    20 │    21 │    22 │    23 │
+│    24 │    25 │    26 │    27 │    28 │    29 │    30 │
+│    31 │       │       │       │       │       │       │
+└───────┴───────┴───────┴───────┴───────┴───────┴───────┘

tests/ModuleTests/Calendar/snapshots/MarkedDayRenderTests/DefaultMarkedDayRender.verified.txt

@@ -0,0 +1,12 @@
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   x │   x │
+│   x │   x │   x │   x │   x │   x │   x │
+│   x │   x │   x │   x │   x │   x │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/MarkedDayRenderTests/DoubleWideMarkedDayRender.verified.txt

@@ -0,0 +1,13 @@
+Double-wide characters will display incorrectly but still tested until rendering can be improved
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   火 │   火 │
+│   火 │   火 │   火 │   火 │   火 │   火 │   火 │
+│   火 │   火 │   火 │   火 │   火 │   火 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/MarkedDayRenderTests/EmojiMarkedDayRender.verified.txt

@@ -0,0 +1,13 @@
+Emojis will display incorrectly in text but output correctly in terminals with UTF-8 encoding.
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │  🤫 │  🤫 │
+│  🤫 │  🤫 │  🤫 │  🤫 │  🤫 │  🤫 │  🤫 │
+│  🤫 │  🤫 │  🤫 │  🤫 │  🤫 │  🤫 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/MarkedDayRenderTests/LongMarkedDayRender.verified.txt

@@ -0,0 +1,12 @@
+┌──────────────────────────────────────────────────────────────┐
+│                          August 2026                         │
+├────────┬────────┬────────┬────────┬────────┬────────┬────────┤
+│    Mon │    Tue │    Wed │    Thu │    Fri │    Sat │    Sun │
+├────────┼────────┼────────┼────────┼────────┼────────┼────────┤
+│        │        │        │        │        │ passed │ passed │
+│ passed │ passed │ passed │ passed │ passed │ passed │ passed │
+│ passed │ passed │ passed │ passed │ passed │ passed │     16 │
+│     17 │     18 │     19 │     20 │     21 │     22 │     23 │
+│     24 │     25 │     26 │     27 │     28 │     29 │     30 │
+│     31 │        │        │        │        │        │        │
+└────────┴────────┴────────┴────────┴────────┴────────┴────────┘

tests/ModuleTests/Calendar/snapshots/MarkedDayRenderTests/SimpleMarkedDayRender.verified.txt

@@ -0,0 +1,12 @@
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   | │   | │
+│   | │   | │   | │   | │   | │   | │   | │
+│   | │   | │   | │   | │   | │   | │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/Calendar/snapshots/StartDayOfWeekTests/StartOfDayRender.verified.txt

@@ -0,0 +1,86 @@
+Start Day: Sunday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Sun │ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │     │   1 │
+│   2 │   3 │   4 │   5 │   6 │   7 │   8 │
+│   9 │  10 │  11 │  12 │  13 │  14 │  15 │
+│  16 │  17 │  18 │  19 │  20 │  21 │  22 │
+│  23 │  24 │  25 │  26 │  27 │  28 │  29 │
+│  30 │  31 │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Monday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Mon │ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │     │   1 │   2 │
+│   3 │   4 │   5 │   6 │   7 │   8 │   9 │
+│  10 │  11 │  12 │  13 │  14 │  15 │  16 │
+│  17 │  18 │  19 │  20 │  21 │  22 │  23 │
+│  24 │  25 │  26 │  27 │  28 │  29 │  30 │
+│  31 │     │     │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Tuesday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Tue │ Wed │ Thu │ Fri │ Sat │ Sun │ Mon │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │     │   1 │   2 │   3 │
+│   4 │   5 │   6 │   7 │   8 │   9 │  10 │
+│  11 │  12 │  13 │  14 │  15 │  16 │  17 │
+│  18 │  19 │  20 │  21 │  22 │  23 │  24 │
+│  25 │  26 │  27 │  28 │  29 │  30 │  31 │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Wednesday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Wed │ Thu │ Fri │ Sat │ Sun │ Mon │ Tue │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │     │   1 │   2 │   3 │   4 │
+│   5 │   6 │   7 │   8 │   9 │  10 │  11 │
+│  12 │  13 │  14 │  15 │  16 │  17 │  18 │
+│  19 │  20 │  21 │  22 │  23 │  24 │  25 │
+│  26 │  27 │  28 │  29 │  30 │  31 │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Thursday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Thu │ Fri │ Sat │ Sun │ Mon │ Tue │ Wed │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │     │   1 │   2 │   3 │   4 │   5 │
+│   6 │   7 │   8 │   9 │  10 │  11 │  12 │
+│  13 │  14 │  15 │  16 │  17 │  18 │  19 │
+│  20 │  21 │  22 │  23 │  24 │  25 │  26 │
+│  27 │  28 │  29 │  30 │  31 │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Friday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Fri │ Sat │ Sun │ Mon │ Tue │ Wed │ Thu │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│     │   1 │   2 │   3 │   4 │   5 │   6 │
+│   7 │   8 │   9 │  10 │  11 │  12 │  13 │
+│  14 │  15 │  16 │  17 │  18 │  19 │  20 │
+│  21 │  22 │  23 │  24 │  25 │  26 │  27 │
+│  28 │  29 │  30 │  31 │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘
+Start Day: Saturday
+┌─────────────────────────────────────────┐
+│               August 2026               │
+├─────┬─────┬─────┬─────┬─────┬─────┬─────┤
+│ Sat │ Sun │ Mon │ Tue │ Wed │ Thu │ Fri │
+├─────┼─────┼─────┼─────┼─────┼─────┼─────┤
+│   1 │   2 │   3 │   4 │   5 │   6 │   7 │
+│   8 │   9 │  10 │  11 │  12 │  13 │  14 │
+│  15 │  16 │  17 │  18 │  19 │  20 │  21 │
+│  22 │  23 │  24 │  25 │  26 │  27 │  28 │
+│  29 │  30 │  31 │     │     │     │     │
+└─────┴─────┴─────┴─────┴─────┴─────┴─────┘

tests/ModuleTests/ModuleTests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <IsPackable>false</IsPackable>
+        <OutputType>Exe</OutputType>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <Using Include="Xunit"/>
+    </ItemGroup>
+
+    <ItemGroup>
+      <PackageReference Include="Microsoft.NET.Test.Sdk" />
+      <PackageReference Include="Verify.XunitV3" />
+      <PackageReference Include="xunit.v3" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\..\src\ModuleCore\ModuleCore.csproj" />
+    </ItemGroup>
+
+</Project>

tests/ModuleTests/TestConstants.cs

@@ -0,0 +1,6 @@
+namespace ModuleTests;
+
+public class TestConstants
+{
+	public const string SnapshotFolderName = "Snapshots";
+}

tests/ModuleTests/TestDataEnumerator.cs

@@ -0,0 +1,15 @@
+using System.Collections;
+
+namespace ModuleTests;
+
+public abstract class TestDataEnumerator<T> : IEnumerable<TheoryDataRow<T>>
+{
+	protected IEnumerable<T> Data { get; init; } = [];
+
+	public IEnumerator<TheoryDataRow<T>> GetEnumerator()
+	{
+		return Data.Select(data => new TheoryDataRow<T>(data)).GetEnumerator();
+	}
+
+	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+}