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

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();
+}