### Question:
Sequence extends ArrayList<Symbol> implements AbstractSequence { public String toString() { if(size() == 0) return "#epsilon"; StringBuilder sb = new StringBuilder(); for(Symbol s : this) { sb.append(s.toString()); sb.append(" "); } return sb.toString(); } Sequence(int size);  Sequence();  Sequence(ArrayList<Symbol> symbols); String toString(); String toDotString(); Sequence copy(); static void printSequenceArray(Sequence[] arr); @Override int dotLength(); @Override void getImpl(StringBuilder sb, Map<Symbol, Integer> symToNum);  }### Answer:
@Test public void stringTest() { assertEquals("#epsilon", empty.toString()); assertEquals("a b ", sequenceAB.toString()); assertEquals("a b c ", sequenceABC.toString()); }