### Question:
TrimFunction implements StringFunction { public String execute(String input) { return input.trim(); }  String execute(String input);  }### Answer:
@Test public void test_execute() { TrimFunction function = new TrimFunction(); assertEquals("zzzzzz", function.execute("zzzzzz ")); assertEquals("zzzzzz", function.execute(" zzzzzz")); assertEquals("ZZZZ", function.execute(" ZZZZ ")); }