### Question:
FileDownloader { public void setContentFileName(String contentFileName) { Validate.notBlank(contentFileName, "contentFileName must be neither null nor blank"); this.contentFileName = contentFileName; }  void setMimeContentType(String mimeContentType); void setContentFileName(String contentFileName);  }### Answer:
@Test(expectedExceptions = NullPointerException.class) public void doesntAllowSetNullContentFileName() { sut.setContentFileName(null); }
@Test(expectedExceptions = IllegalArgumentException.class) public void doesntAllowSetEmptyContentFileName() { sut.setContentFileName(""); }