unit_tests.sh fails in last check with timeouted server connection

Running `unit_tests.sh` gives an assert in the `unit-test-client.log`:

```
...
7/8 Disable byte timeout: OK
8/8 Connection timeout: 
Line 679: assertion error for 'rc == -1 && (*__errno_location ()) == 110': 
```

This causes the test suite to fail.