[jr-rk]

Purpose

The dspace_rest_client/ production fixes that were previously bundled with the
test/CI PR, split out per review so the test PR stays scoped. Stacked on
test/clarin-usage-coverage (base of this PR) — it supplies the _helpers
builders, pytest.ini markers and the differential-contract job these tests
run under. Merge that PR first.

Targets dtq. The failure-mode assertions are dtq_only and deselected on the
main leg; main carries the same bugs, but propagating these fixes to main is
deliberately out of scope here.

Fixes (each characterization-tested: test written first, then the method)

Method	Was	Now
get_bundle_by_name / get_items_from_collection / get_resource_policy	NoneType subscript crash on non-200	clean None / []
get_resource_policy	IndexError on empty policy list; no error/empty distinction	None, records last_err
get_user_by_email	truthy uuid-less User on 404 (slips past if user:)	None, records last_err, no noisy 404 log
create_submit_group	Group(None) crash on a 201 with empty body	None
add_member	posts a bare /epersons/{uuid} href → DSpace 422/404	canonical /eperson/epersons/{uuid}
Group(None) / User(None)	TypeError	empty object
get_owningCollection (dtq-only)	empty truthy Collection on non-200 → ISstag _audit.py 401-reauth was dead code	None + last_err

Verified locally

Leg A (full suite, dtq impl with these fixes): 137 pass.

[vidiecan]

Rebased onto the new #23 head (dtq a62a63e) + review fixes

New head: 4eaf688 (rebased commit 88c4c56 + one review commit), stacked on #23 13ba16c.

Conflict resolution

• tests/test_clarin_write.py - this PR's dtq_only test_posts_eperson_uri_and_returns_true_on_204 collided with test: CLARIN consumer-contract suite + main-tailored differential CI #23's new shared add_member body test. Kept test: CLARIN consumer-contract suite + main-tailored differential CI #23's shared test (asserts the uri-list body, ends in /epersons/{uuid}) and dropped the dtq_only duplicate, see the add_member row below.
• client.py applied cleanly on top of dtq's fix(client): log expected 401/404 fetch failures as concise warnings #28/fix(client): follow pagination and verify counts in list getters #29 changes (fetch_resource concise 401/404 warnings, _fetch_all_pages); nothing from dtq was reverted.

Review fixes (each test written first and seen failing)

Finding	Change	Test
get_items_from_collection turned any failed request into [] with no last_err, so the consumers' paging loop (which stops on None/empty) silently truncated	Goes through fetch_resource; returns None on failure (last_err set on a non-200). I chose None over raising because it keeps this PR's goal (a failed call stops cleanly, no crash) and the consumer loop (dspace-import get_all_items) already stops on is None, while None + last_err now tells an error from the real end ([])	test_non_200_returns_none_and_records_last_err
get_user_by_email: DSpace answers an unknown email with 204, not 404	204 = clean miss: None, no log, no last_err. 404 (misconfiguration), 401/403/5xx, an unparseable or uuid-less body: None, logged at ERROR, last_err kept. The raw email is never logged. The blanket except Exception is gone, so a timeout propagates instead of looking like a clean miss	test_204_no_content_is_a_clean_miss, test_error_status_returns_none_logs_error_and_records_last_err (404/401/403/500, email not in logs), test_transport_error_is_not_a_clean_miss; contract test now uses 204
Group(None)/User(None) accepted, so a failed create returned a truthy uuid-less object	create_group/create_user return None when the parsed body has no uuid; create_submit_group checks j.get('uuid')	TestCreateGroupAndUser (201 typed, shared; failure None, dtq_only), test_201_without_uuid_returns_none
get_owningCollection: unparseable 200 did not record last_err; a timeout aborted the caller's prefetch loop	Unparseable 200 sets last_err; requests.RequestException is caught, logged, None returned	test_unparseable_200_returns_none_and_sets_last_err, test_transport_error_returns_none_without_raising
The add_member comment / dtq_only claimed the bare /epersons/{uuid} href "does not resolve"	Comment corrected (DSpace matches only the trailing UUID); canonical /eperson/epersons/{uuid} kept; the dtq_only test is replaced by #23's shared one	shared add_member body test

Note on transport errors: last_err holds a Response, and the ISstag _audit.py predicate dereferences last_err.status_code, so it is not set to an exception object. In get_owningCollection a None result is always a failure, so returning None with a logged error is unambiguous. In get_user_by_email, None with no last_err means "no such user", so a timeout has to propagate instead.

Verified locally

• Full suite + --cov-fail-under=70: 163 passed, 73.9% coverage.
• Differential contract: dtq leg 66 passed; main leg 46 passed, 20 dtq_only deselected.
• Python 3.8.20: 163 passed.
• Offline consumer check (dspace-rest-test, read-only): every DSpaceClient call it makes (26 call shapes, incl. create_clarinlruallowances, get_clarinlruallowances_by_bitstream_and_user, get_user_by_email, add_member, create_submit_group) binds to the rebased signatures, and the return contracts it relies on hold (User/Group with uuid, None on miss, True from add_member, allowance list with _links). Also checked get_resource_policy(...)["id"] and get_bundle_by_name.

Deferred (not changed here)

• One fetch helper for all the CLARIN getters (several still open-code api_get + parse_json).
• get_resource_policy returns policies[0] of a possibly multi-policy list.
• create_dso still crashes on a 201 with an empty body (new_dso["type"] on None).