### Question:
StringUtil { public static boolean isBlank(final String string) { return string == null || string.trim().length() == 0; } private  StringUtil(); static boolean isNullOrEmpty(final String string); static boolean isBlank(final String string); static String convertStreamToString(final InputStream is, final Charset charset); static String convertStreamToUTF8String(final InputStream is); static String clipString(String input, int numChars, boolean appendEllipses); static String convertArrayToString(String[] stringArr); static String convertSetToString(Set<String> stringSet); static String trimOrPadString(String str, int len, char pad); static final String UTF_8; }### Answer:
@Test public void isBlank_empty_string() { assertTrue(StringUtil.isBlank("")); }
@Test public void isBlank_blank_string() { assertTrue(StringUtil.isBlank(" ")); }
@Test public void isBlank_non_blank_string() { assertFalse(StringUtil.isBlank("abcde")); }