fix(simulator): Patch BaseTransaction.resolve() to prevent updating timestamp

[msbrogli]

Acceptance criteria

1. Patch BaseTransaction.resolve() to prevent updating timestamp.

Notice that BaseTransaction.resolve() calls BaseTransaction.start_mining(), which updates the timestamp using time.time() if mining takes more than two seconds. This might be causing tests to randomly fail.

The reasons for tests to randomly fail is that Transaction.start_mining() is using time.time() to get the timestamp (instead of reactor.seconds()). As the reactor time is not related to the current timestamp, the transaction timestamp can be too much in the future raising a InvalidNewTransaction exception.

For more details, check out this part of the code: https://github.com/HathorNetwork/hathor-core/blob/master/hathor/manager.py#L976-L982

[glevco]

Just curious, why would the timestamp update make tests fail?

[msbrogli]

Just curious, why would the timestamp update make tests fail?

Because Transaction.start_mining() is using time.time() to get the timestamp (instead of reactor.seconds()). As the reactor time is not related to the current timestamp, the transaction timestamp can be too much in the future raising a InvalidNewTransaction exception.

Check out this part of the code: https://github.com/HathorNetwork/hathor-core/blob/master/hathor/manager.py#L976-L982

[jansegre]

Do we still need the timestamp update? Couldn't we just remove it? Or default it to not doing an update and requiring a "timestamp source", like a reactor to do it?

Mostly I'd prefer to avoid doing patches.

[codecov]

Codecov Report

Merging #641 (0cf0e1d) into master (84a7516) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #641      +/-   ##
==========================================
- Coverage   84.06%   84.05%   -0.01%     
==========================================
  Files         245      245              
  Lines       20270    20277       +7     
  Branches     2758     2758              
==========================================
+ Hits        17039    17043       +4     
- Misses       2635     2636       +1     
- Partials      596      598       +2     

Impacted Files	Coverage Δ
hathor/simulator/simulator.py	94.61% <100.00%> (+0.23%)	⬆️

... and 2 files with indirect coverage changes