### Question:
StringUtils { public static boolean isBlank(String text) { return (text == null || text.trim().length() == 0); } private  StringUtils(); static boolean isBlank(String text); static boolean anyBlank(String... texts);  }### Answer:
@Test public void isBlank_returns_true_when_text_is_null() { assertTrue(StringUtils.isBlank(null)); }
@Test public void isBlank_returns_true_when_text_is_empty() { assertTrue(StringUtils.isBlank("")); }
@Test public void isBlank_returns_true_when_text_is_blank() { assertTrue(StringUtils.isBlank(" \t\r\n")); }