### Question:
ListArgumentSet implements ArgumentSet { @Override public boolean has(String argument) { return arguments.contains(argument); } ListArgumentSet(List<String> arguments); @Override String get(int index); @Override int length(); @Override List<String> getAll(); @Override boolean isEmpty(); @Override boolean has(String argument); @Override String join(); @Override String[] toArray();  }### Answer:
@Test public void has() { assertTrue(listArgumentSet.has("a")); assertTrue(listArgumentSet.has("c")); assertFalse(listArgumentSet.has("e")); }