### Question:
UTF7Base64Helper { public int getSextet (final int ch) { if (ch >= 128) return -1; return m_aInverseAlphabet[ch]; } UTF7Base64Helper(@Nonnull @Nonempty final String sAlphabet); int getSextet(final int ch); boolean contains(final char ch); byte getChar(final int sextet);  }### Answer:
@Test public void testGetSextet () { assertEquals (0, tested.getSextet ((byte) 'A')); assertEquals (63, tested.getSextet ((byte) '/')); assertEquals (-1, tested.getSextet ((byte) ',')); }