Fix socket issues

[beliaev-maksim]

• Added pytest filter to ensure that we capture warnings as errors
• Revert socket change
• Added comment why this is the behaviour we have
• Added run on the test to fix coverage

closes #689 closes #691

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c46cb06) 99.50% compared to head (5d75ed8) 99.93%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #693 +/- ## ========================================== + Coverage 99.50% 99.93% +0.42% ========================================== Files 9 9 Lines 3044 3044 ========================================== + Hits 3029 3042 +13 + Misses 15 2 -13 ```

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