Fix possible StringIndexOutOfBoundsException

[arthurscchan]

This PR proposes a fix for #1141 .

[gotson]

do you think you could add a test covering this ?

[arthurscchan]

@gotson Really sorry for missing your comment. I have added in the unit test for the removeQuotation method.

[gotson]

@gotson Really sorry for missing your comment. I have added in the unit test for the removeQuotation method.

the test code doesn't compile

[gotson]

i've refactored your test code:

@ParameterizedTest
  @MethodSource
  public void removeQuotation(String input, String expected) throws SQLException {
    assertThat(ExtendedCommand.removeQuotation(input)).isEqualTo(expected);
  }

  private static Stream<Arguments> removeQuotation() {
    return Stream.of(
        Arguments.of(null, null), // Null String
        Arguments.of("'", "'"), // String with one single quotation only
        Arguments.of("\"", "\""), // String with one double quotation only
        Arguments.of("'Test\"", "'Test\""), // String with two mismatch quotations
        Arguments.of("'Test'", "Test"), // String with two matching single quotations
        Arguments.of("\"Test\"", "Test"), // String with two matching double quotations
        Arguments.of("'Te's\"t'", "Te's\"t") // String with more than two quotations
    );
  }

[arthurscchan]

@gotson, I have changed the parameter name but forget to push in the new one. Sorry for my careless mistake. And thanks for helping me to fix it.