tests: round-trip 258 option codes from the registries, recording the 86 that cannot close the cycle

README.rst

@@ -386,6 +386,17 @@ and ``make test-all`` regenerates them before running the whole suite:
 The same fixtures back the demonstration scripts in
 ``examples/legacy_smoke/``, which read them as ``../captures/…``.
 
+One of the generators works differently from the rest and is worth knowing about.
+``examples/generators/options.py`` does not describe packets it wants; it asks the
+library which option, chunk, parameter, message, frame and block codes it
+registers, and then constructs one of each through the public construction API,
+parses it back, and constructs it again from what was parsed. The
+``options-*.pcap`` captures are the cases that survive that round trip, so they
+record what this version of ``pcapkit`` builds rather than what a third-party
+tool builds. ``tests/protocols/test_option_roundtrip_unit.py`` runs the same
+cases without needing a fixture at all, and carries a table of the ones that do
+not yet close the cycle, each named against the defect that stops it.
+
 Continuous integration runs the ``make test`` selection, since the fixtures are
 not in the repository. ``tshark`` is only required to exercise the PyShark
 engine, and is not needed by the test suite.

examples/generators/make_samples.py

@@ -20,6 +20,7 @@
 :file:`pcap.py`     the ``.pcap`` captures the unit and runtime tests read
 :file:`pcapng.py`   the ``.pcapng`` captures the regression tests read
 :file:`legacy.py`   the extra captures ``examples/legacy_smoke/`` reads
+:file:`options.py`  the ``options-*.pcap`` option-coverage captures
 =================== ==========================================================
 
 They are loaded by path rather than imported by name, since this directory is
@@ -44,8 +45,12 @@
 HERE = pathlib.Path(__file__).resolve().parent
 #: Destination directory for every generated capture.
 DEST = ROOT / 'examples' / 'captures'
-#: Generator modules, in the order they are run.
-GENERATORS = ('pcap', 'pcapng', 'legacy')
+#: Generator modules, in the order they are run. :file:`options.py` runs last
+#: because it is the only one that builds its captures out of :mod:`pcapkit`'s
+#: own construction output, so a failure in it is a statement about the library
+#: rather than about the fixture -- and reading it after the others have already
+#: printed keeps that distinction visible in the log.
+GENERATORS = ('pcap', 'pcapng', 'legacy', 'options')
 
 
 def load(name: 'str') -> 'ModuleType':