### Question:
Base64Codec implements IByteArrayCodec { @Override public int getMaximumDecodedLength (final int nLen) { return MathHelper.getRoundedUp (nLen, 4) * 3 / 4; } Base64Codec(); @Override int getMaximumEncodedLength(final int nLen); void encode(@Nullable final byte [] aDecodedBuffer,
                      @Nonnegative final int nOfs,
                      @Nonnegative final int nLen,
                      @Nonnull @WillNotClose final OutputStream aOS); @Nullable @ReturnsMutableCopy @Override byte [] getEncoded(@Nullable final byte [] aDecodedBuffer, @Nonnegative final int nOfs, @Nonnegative final int nLen); @Override int getMaximumDecodedLength(final int nLen); void decode(@Nullable final byte [] aEncodedBuffer,
                      @Nonnegative final int nOfs,
                      @Nonnegative final int nLen,
                      @Nonnull @WillNotClose final OutputStream aOS); @Nullable @ReturnsMutableCopy @Override byte [] getDecoded(@Nullable final byte [] aEncodedBuffer, @Nonnegative final int nOfs, @Nonnegative final int nLen);  }### Answer:
@Test public void testGetDecodedLength () { final Base64Codec aBase64 = new Base64Codec (); assertEquals (0, aBase64.getMaximumDecodedLength (0)); for (int i = 1; i <= 4; ++i) assertEquals (3, aBase64.getMaximumDecodedLength (i)); for (int i = 5; i <= 8; ++i) assertEquals (6, aBase64.getMaximumDecodedLength (i)); }