Unsubscribe error on ShapeShift modal close

[jacogr]

• allow for double unsubscribe
• tests for subscribe/unsubscribe
• reproduce already-unsubscribed failure

[ngotchac]

Would prefer to keep the unsubscribe call in the onUnmount as well

[jacogr]

Doesn't make sense having it in both places, however with the introduced flag it cannot hurt.

However, going to take a fresh look at this instead - first need a test that reproduces the error before fixing, so we can be sure instead of (probably) coming back at some point. A bit blind here and this may or may not do the trick, which is not acceptable.

[jacogr]

@ngotchac As expected, looked in the wrong place. With auto-unsubscribe (which didn't use the proper unsubscribe function, just set the values null) we caught an error when completed and trying again in unmounting the component. Fixed at source.

[ngotchac]

Looks good from a code point of view, however cannot really test fully with Shapeshift

[ngotchac]

Looks good. Would just get rid of the console.log here https://github.com/ethcore/parity/blob/jg-shapeshift-unsubscribe/js/src/modals/Shapeshift/shapeshift.js#L269 (just adds some noise IMO)

[jacogr]

Actually find that info quite useful, however that is for another PR since this one has not touched the modal, nor introduced that code - have one open where the modal is addressed, i.e. https://github.com/ethcore/parity/pull/4035