### Question:
CharacterReader { char consume() { bufferUp(); char val = isEmpty() ? EOF : charBuf[bufPos]; bufPos++; return val; } CharacterReader(Reader input, int sz);  CharacterReader(Reader input);  CharacterReader(String input); int pos(); boolean isEmpty(); char current(); void advance(); String consumeTo(char c); String consumeToAny(final char... chars); @Override String toString();  }### Answer:
@Test public void consume() { CharacterReader r = new CharacterReader("one"); assertEquals(0, r.pos()); assertEquals('o', r.current()); assertEquals('o', r.consume()); assertEquals(1, r.pos()); assertEquals('n', r.current()); assertEquals(1, r.pos()); assertEquals('n', r.consume()); assertEquals('e', r.consume()); assertTrue(r.isEmpty()); assertEquals(CharacterReader.EOF, r.consume()); assertTrue(r.isEmpty()); assertEquals(CharacterReader.EOF, r.consume()); }