public void CanReadSimpleContentWhileCaching(int readAhead)
{
const string testString = "Hello world!";
using var textReader = new StringReader(testString);
using var charReader = new CharReader(textReader);
Assert.That(charReader.PeekString(readAhead),
Is.EqualTo(testString.Substring(0, Math.Min(testString.Length, readAhead))));
Assert.That(charReader.PeekChar(), Is.EqualTo('H'));
Assert.That(charReader.ReadChar(), Is.EqualTo('H'));
Assert.That(charReader.PeekChar(), Is.EqualTo('e'));
Assert.That(charReader.ReadChar(), Is.EqualTo('e'));
Assert.That(charReader.PeekChar(), Is.EqualTo('l'));
Assert.That(charReader.ReadChar(), Is.EqualTo('l'));
Assert.That(charReader.PeekChar(), Is.EqualTo('l'));
Assert.That(charReader.ReadChar(), Is.EqualTo('l'));
Assert.That(charReader.PeekChar(), Is.EqualTo('o'));
Assert.That(charReader.ReadChar(), Is.EqualTo('o'));
Assert.That(charReader.PeekChar(), Is.EqualTo(' '));
Assert.That(charReader.ReadChar(), Is.EqualTo(' '));
Assert.That(charReader.PeekString(6), Is.EqualTo("world!"));
Assert.That(charReader.PeekChar(), Is.EqualTo('w'));
Assert.That(charReader.ReadChar(), Is.EqualTo('w'));
Assert.That(charReader.PeekChar(), Is.EqualTo('o'));
Assert.That(charReader.ReadChar(), Is.EqualTo('o'));
Assert.That(charReader.PeekChar(), Is.EqualTo('r'));
Assert.That(charReader.ReadChar(), Is.EqualTo('r'));
Assert.That(charReader.PeekChar(), Is.EqualTo('l'));
Assert.That(charReader.ReadChar(), Is.EqualTo('l'));
Assert.That(charReader.PeekChar(), Is.EqualTo('d'));
Assert.That(charReader.ReadChar(), Is.EqualTo('d'));
Assert.That(charReader.PeekChar(), Is.EqualTo('!'));
Assert.That(charReader.ReadChar(), Is.EqualTo('!'));
Assert.That(charReader.PeekChar(), Is.Null);
Assert.That(charReader.ReadChar(), Is.Null);
}