public void ReplaceTest()
{
var newText1 = text.Replace('i', '1');
Assert.AreEqual(newText1.Text, text.Text.Replace('i', '1'));
Assert.AreEqual(newText1.AnySpanReferenceEquals(text), false);
var newText2 = text.Replace("t", "tt");
var newText3 = text.Replace("1", (string)null);
var newText4 = text.Replace("t", (string)null);
Assert.AreEqual(newText2.Text, text.Text.Replace("t", "tt"));
Assert.AreEqual(newText2.AnySpanReferenceEquals(text), false);
Assert.AreEqual(newText3.Text, text.Text);
Assert.AreEqual(newText3.AnySpanReferenceEquals(text), false);
Assert.AreEqual(newText4.Text, text.Text.Replace("t", null));
Assert.AreEqual(newText4.AnySpanReferenceEquals(text), false);
}