1 WrapperTest.java

  public static class SplitWordTests {
    @Test
    public void splitOneWord() throws Exception {
      assertThat(wrap("word", 2), equalTo("wo\nrd"));
    }
  }

2 Wrapper.java

public class Wrapper {
  public static String wrap(String s, int col) {
    if (s.length() <= col)
      return s;
    else
      return (s.substring(0, col) + "\n" + s.substring(col));
  }
}