public void T01_TestRemoveAndReplace()
{
const string TestString = "Hello, world!";
Assert.AreEqual(TestString, TestString.Replace((char[])null, "foo"));
Assert.AreEqual(TestString, TestString.Replace(new char[] { 'a', 'b', 'c' }, "foo"));
Assert.AreEqual("Hellfoo, wfoofoold!", TestString.Replace(new char[] { 'a', 'o', 'c', 'r' }, "foo"));
Assert.AreEqual("Hellfoo, wfoorld!", TestString.Replace(new char[] { 'o' }, "foo"));
Assert.AreEqual("Hell, wrld", TestString.Remove('a', 'o', 'b', '!'));
}