The NMT state transition from INITIALISING to PRE-OPERATIONAL causes
the heartbeat to start automatically if the parameter is non-zero in
object 0x1017:00.  This check however raises an exception if the
object does not even exist.

Cover this state in tests and explicitly ignore a KeyError when asking
for the object.

…658)

* eds: fix LowLimit/HighLimit parsing for all signed integer types

- Reimplement _calc_bit_length() (only handled INTEGER8/16/32/64)
  using the same structure types used in ODVariable.
- Log a warning instead of silently ignoring invalid limit values
- Add EDS test entries in sample.eds for INTEGER24/40/48/56 with
  hex-encoded negative limits
- Extend test_record_with_limits and add test_invalid_limit_logs_warning

* Enhance test coverage for _revert_variable() branches (without default_raw).

* Renamed _convert_variable → _decode_from_eds and _revert_variable → _encode_to_eds

Co-authored-by: André Colomb <src@andre.colomb.de>
Co-authored-by: Frieder Schüler <frieder.schueler@bizerba.com>

When importing an EDS/DCF file, any key that is not part of the CiA 306
standard field set is now collected into a custom_options dict on the object.
This allows applications to round-trip vendor-specific metadata without
losing it.

* Use getattr/setattr instead of __dict__ access for array entry attributes.

Co-authored-by: FedericoSpada <FedericoSpada@users.noreply.github.com>
Co-authored-by: André Colomb <src@andre.colomb.de>

- Fix bug where an exception in one EMCY callback would abort all
  subsequent callbacks; now logs the exception and continues
- Add test for callback exception handling (verifies fix)
- Add tests for EmcyConsumer initialization, multiple callback order,
  error reset variants, wait timeout edge cases, concurrent errors
- Add tests for EmcyError initialization types and str representation
- Add tests for EmcyProducer initialization, send/reset edge cases
- Add TestEmcyIntegration class using network.subscribe() for
  producer-consumer roundtrip tests
- Remove superfluous inline comments per reviewer feedback (acolomb)
- Convert leading comment to docstring in test_emcy_consumer_on_emcy

Addresses review feedback from PR #604 by yuvraj-kolkar17.

* Factor out mock_rx_thread().

Simplify by extracting Thread creation and starting, and joining to
one central helper function, including the emcy_received condition
lock to avoid race conditions.

Co-authored-by: André Colomb <src@andre.colomb.de>
Co-authored-by: Frieder Schüler <frieder.schueler@bizerba.com>