### Question:
StringUtils { public static boolean isQuoted(String str) { if (str == null || str.isEmpty()) { return false; } return (str.startsWith("\"") && str.endsWith("\"")); } private  StringUtils(); static boolean isEmpty(final String s); static boolean nonEmpty(final String s); static boolean hasNonEmpty(final String... values); static boolean isQuoted(String str); static String createQuotedString(final String str); static String createQuotedStringIfNotNumeric(String str); static String replaceIllegalCharsAttribute(final String value); static String replaceIllegalCharsForDataObjects(final String value); static String revertIllegalCharsAttribute(final String value); static String createUnquotedString(String str);  }### Answer:
@Test public void testIsQuotedConstantNull() { assertFalse(StringUtils.isQuoted(null)); }
@Test public void testIsQuotedConstantEmpty() { assertFalse(StringUtils.isQuoted("")); }
@Test public void testIsQuotedConstantOpeningQuote() { assertFalse(StringUtils.isQuoted("\"a")); }
@Test public void testIsQuotedConstantClosingQuote() { assertFalse(StringUtils.isQuoted("a\"")); }
@Test public void testIsQuotedConstantOpeningAndClosingQuote() { assertTrue(StringUtils.isQuoted("\"a\"")); }