FilterReader - Find Certain Sequences Of Letters

I've created a class that extends FilterReader, that is to be used to find certain sequences of letters. I plan on using this code to demonstrate an observer, observable design pattern later on. Here is my code:
 
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FilterReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Arrays;
public class CaroReaderV2 extends FilterReader {
 
[Code] .....

Now my question is, how do I go about testing this in a main class? How would I pass in a reader to the constructor? How would I make sure that everything is working correctly?