tests broken on CI - test with mock Gmail API instead

[tomholub]

We'll have to do something about these tests.

Originally posted by @tomholub in #281 (comment)

[tomholub]

On flowcrypt-browser repo we use this mock of Google oauth2 / Gmail API:
https://github.com/FlowCrypt/flowcrypt-browser/blob/master/test/source/mock/google/google-endpoints.ts

@DenBond7 what approach do we use on Android? Could you point us to some source files for inspiration?

[DenBond7]

@tomholub we use Gmail API recently. Before we had only IMAP realization. That's why we don't have any tests for Gmail API yet.

[tomholub]

Not good. That means on Android, we only test all of this functionality with IMAP server, we don't actually test the Gmail API functionality. But the difference should generally only be the IMAP/API layer, hopefully not so error prone.

[DenBond7]

Agree. But the code made to support Gmail API and IMAP at the same time. It means we have the same code. Just in some place we call Gmail API or IMAP. The behavior should be the same. UI tests will be the same. There is only one difference - error messages.

But anyway we should add mock realization for Gmail API to be sure that all works as expected.

[DenBond7]

But the difference should generally only be the IMAP/API layer, hopefully not so error prone.

You are totally correct

[tomholub]

I'll close this for now, we haven't encountered many Gmail specific bugs.