1 WrapperTest.java

@RunWith(Suite.class)
@Suite.SuiteClasses({
  WrapperTest.DegenerateTests.class})

public class WrapperTest {
  public static class DegenerateTests {
    @Test
    public void emptyString() throws Exception {
      assertThat(wrap("", 1), equalTo(""));
    }

    @Test
    public void stringShorterThanCol() throws Exception {
      assertThat(wrap("this", 10), equalTo("this"));
    }
  }
} 

2 Wrapper.java

public class Wrapper {
  public static String wrap(String s, int col) {
     return s;
  }
}