Unconditional branch in EncodeTest::aisDecodeEncode

[Zoybean]

The following branch in EncodeTest::aisDecodeEncode is unconditional and prevents the test from verifying any message encodings:

if (!(msg instanceof AisPositionMessage) || !(msg instanceof AisMessage4)
        || !(msg instanceof AisStaticCommon)) {
    vdm = new Vdm();
    continue;
}

The branch is unconditional because the three classes are mutually exclusive subclasses of AisMessage, and the condition is equivalent to testing if msg is an instance of all three:

!(msg instanceof AisPositionMessage && msg instanceof AisMessage4
        && msg instanceof AisStaticCommon)

It appears the intention was:

if (!(msg instanceof AisPositionMessage || msg instanceof AisMessage4
        || msg instanceof AisStaticCommon)) {
    vdm = new Vdm();
    continue;
}

However, the purpose of this is conditional expression is unclear, so I cannot be certain this is correct.

Note:

Due to #35, the change above causes an exception when the test is executed, as one of the later statements calls msg.getEncoded() on an instance of AisMessage24.

[tbsalling]

Hi @Zoybean - thanks; your contribution is welcomed.

Can you please supply a pull request with proposed changes - without reducing current unit test coverage?

Thanks,
/Thomas.