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Test fails in relational_operand due to test code, not functionality. #1205
Description
Bug Report
Description
Test fails in relational_operand.
Reproducibility
Run test container from datajoint/datajoint-python/docker-comose.yml with Python version 3.11 or 3.9 presets.
Stack trace from pytest:
_________________ TestDjTop.test_top_restriction_with_keywords _________________
self = <tests.test_relational_operand.TestDjTop object at 0x7563c4b042e0>
schema_simp_pop = Schema `djtest_relational`
def test_top_restriction_with_keywords(self, schema_simp_pop):
select = SelectPK() & dj.Top(limit=9, order_by=["select desc"])
key = KeyPK() & dj.Top(limit=9, order_by="key desc")
assert select.fetch(as_dict=True) == [
{"id": 2, "select": 8},
{"id": 2, "select": 6},
{"id": 1, "select": 4},
{"id": 2, "select": 4},
{"id": 1, "select": 3},
{"id": 1, "select": 2},
{"id": 2, "select": 2},
{"id": 1, "select": 1},
{"id": 0, "select": 0},
]
> assert key.fetch(as_dict=True) == [
{"id": 2, "key": 6},
{"id": 2, "key": 5},
{"id": 1, "key": 5},
{"id": 0, "key": 4},
{"id": 1, "key": 4},
{"id": 2, "key": 4},
{"id": 0, "key": 3},
{"id": 1, "key": 3},
{"id": 2, "key": 3},
]
E AssertionError: assert [{'id': 2, 'k...key': 4}, ...] == [{'id': 2, 'k...key': 4}, ...]
E
E At index 1 diff: {'id': 1, 'key': 5} != {'id': 2, 'key': 5}
E Use -v to get more diff
tests/test_relational_operand.py:629: AssertionError
Additional Research and Context
Offending lines are these: https://github.com/datajoint/datajoint-python/blob/eef7e59316a05349dc662f34928403808d93e49c/tests/test_relational_operand.py#L631-632
Original:
assert key.fetch(as_dict=True) == [
{"id": 2, "key": 6},
{"id": 2, "key": 5}, # <<
{"id": 1, "key": 5}, # <<
{"id": 0, "key": 4},
{"id": 1, "key": 4},
{"id": 2, "key": 4},
{"id": 0, "key": 3},
{"id": 1, "key": 3},
{"id": 2, "key": 3},
]Suggested fix: Swap lines for key==5:
assert key.fetch(as_dict=True) == [
{"id": 2, "key": 6},
{"id": 1, "key": 5},
{"id": 2, "key": 5},
{"id": 0, "key": 4},
{"id": 1, "key": 4},
{"id": 2, "key": 4},
{"id": 0, "key": 3},
{"id": 1, "key": 3},
{"id": 2, "key": 3},
]Additional
Relevant for open PR #1197
Activity
tests: fix expected ordering in relational_operand (datajoint#1205)
dimitri-yatsenko commentedon Jan 7, 2026
This is related to #1242. The order is not deterministic.
dimitri-yatsenko commentedon Jan 8, 2026
This issue has been resolved in the DataJoint 2.0 codebase.
The test was updated to use order-independent comparison since
dj.Toponly guarantees which elements are selected, not their order when there are ties in theorder_bycolumn:The test now correctly validates the set of returned rows rather than assuming a specific order for rows with equal
order_byvalues.Related: #1242 (closed)
dimitri-yatsenko commentedon Jan 8, 2026
Update: DataJoint 2.0 fixes
dj.Topto properly preserve theORDER BYclause in query results.The test has been updated to verify ordering is preserved. To ensure deterministic results when there are ties, the test now uses a secondary sort key:
The fix ensures that:
dj.Topordering is applied to fetch results (previously could be lost)Commit: test(Top): verify dj.Top preserves ORDER BY in results
test(Top): verify dj.Top preserves ORDER BY in results