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Merged
eerxuan merged 2 commits into from
May 15, 2026
Merged

Add $sum accumulator tests #186

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36d3fbe
`sum` test cases
alinaliBQ May 14, 2026
d49f2d5
Merge branch 'main' into sum
eerxuan May 15, 2026
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Empty file added documentdb_tests/compatibility/tests/core/operator/accumulators/sum/__init__.py
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249 changes: 249 additions & 0 deletions documentdb_tests/compatibility/tests/core/operator/accumulators/sum/test_sum_boundary.py
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"""Tests for $sum accumulator: integer boundary values, large groups, and negative zero."""

from __future__ import annotations

import pytest
from bson import Int64

from documentdb_tests.compatibility.tests.core.operator.accumulators.utils.accumulator_test_case import ( # noqa: E501
AccumulatorTestCase,
)
from documentdb_tests.framework.assertions import assertSuccess
from documentdb_tests.framework.executor import execute_command
from documentdb_tests.framework.parametrize import pytest_params
from documentdb_tests.framework.test_constants import (
DECIMAL128_NEGATIVE_ZERO,
DOUBLE_FROM_INT64_MAX,
DOUBLE_NEGATIVE_ZERO,
INT32_MAX,
INT32_MAX_MINUS_1,
INT32_MIN,
INT32_MIN_PLUS_1,
INT32_OVERFLOW,
INT32_UNDERFLOW,
INT64_MAX,
INT64_MAX_MINUS_1,
INT64_MIN,
INT64_MIN_PLUS_1,
)

# Property [Integer Boundary Values]: boundary values at the edges of int32
# and Int64 ranges stay in their original type when no overflow occurs, and
# promote to the next wider type when the sum crosses the boundary by one.
SUM_INTEGER_BOUNDARY_TESTS: list[AccumulatorTestCase] = [
AccumulatorTestCase(
"boundary_int32_max_single",
docs=[{"v": INT32_MAX}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT32_MAX, "type": "int"},
msg="$sum should keep int32_max as int32 when it is the only value",
),
AccumulatorTestCase(
"boundary_int32_min_single",
docs=[{"v": INT32_MIN}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT32_MIN, "type": "int"},
msg="$sum should keep int32_min as int32 when it is the only value",
),
AccumulatorTestCase(
"boundary_int64_max_single",
docs=[{"v": INT64_MAX}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT64_MAX, "type": "long"},
msg="$sum should keep int64_max as Int64 when it is the only value",
),
AccumulatorTestCase(
"boundary_int64_min_single",
docs=[{"v": INT64_MIN}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT64_MIN, "type": "long"},
msg="$sum should keep int64_min as Int64 when it is the only value",
),
AccumulatorTestCase(
"boundary_int32_max_no_overflow",
docs=[{"v": INT32_MAX_MINUS_1}, {"v": 1}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT32_MAX, "type": "int"},
msg="$sum should stay int32 when int32_max-1 + 1 equals int32_max",
),
AccumulatorTestCase(
"boundary_int32_max_overflow",
docs=[{"v": INT32_MAX_MINUS_1}, {"v": 2}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": Int64(INT32_OVERFLOW), "type": "long"},
msg="$sum should promote to Int64 when int32_max-1 + 2 overflows int32",
),
AccumulatorTestCase(
"boundary_int32_min_no_overflow",
docs=[{"v": INT32_MIN_PLUS_1}, {"v": -1}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT32_MIN, "type": "int"},
msg="$sum should stay int32 when int32_min+1 + (-1) equals int32_min",
),
AccumulatorTestCase(
"boundary_int32_min_overflow",
docs=[{"v": INT32_MIN_PLUS_1}, {"v": -2}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": Int64(INT32_UNDERFLOW), "type": "long"},
msg="$sum should promote to Int64 when int32_min+1 + (-2) overflows int32",
),
AccumulatorTestCase(
"boundary_int64_max_no_overflow",
docs=[{"v": INT64_MAX_MINUS_1}, {"v": Int64(1)}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT64_MAX, "type": "long"},
msg="$sum should stay Int64 when int64_max-1 + 1 equals int64_max",
),
AccumulatorTestCase(
"boundary_int64_max_overflow",
docs=[{"v": INT64_MAX_MINUS_1}, {"v": Int64(2)}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": DOUBLE_FROM_INT64_MAX, "type": "double"},
msg="$sum should promote to double when int64_max-1 + 2 overflows Int64",
),
AccumulatorTestCase(
"boundary_int64_min_no_overflow",
docs=[{"v": INT64_MIN_PLUS_1}, {"v": Int64(-1)}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": INT64_MIN, "type": "long"},
msg="$sum should stay Int64 when int64_min+1 + (-1) equals int64_min",
),
AccumulatorTestCase(
"boundary_int64_min_overflow",
docs=[{"v": INT64_MIN_PLUS_1}, {"v": Int64(-2)}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": -DOUBLE_FROM_INT64_MAX, "type": "double"},
msg="$sum should promote to double when int64_min+1 + (-2) overflows Int64",
),
]

# Property [Large Groups]: $sum correctly accumulates values across large
# groups without precision loss or type promotion.
SUM_LARGE_GROUP_TESTS: list[AccumulatorTestCase] = [
AccumulatorTestCase(
"large_group_10k_int1",
docs=[{"v": 1} for _ in range(10_000)],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "value": "$result", "type": {"$type": "$result"}}},
],
expected={"value": 10_000, "type": "int"},
msg="$sum should produce 10000 (int32) for 10000 documents with int(1)",
),
]

SUM_BOUNDARY_AND_LARGE_GROUP_TESTS = SUM_INTEGER_BOUNDARY_TESTS + SUM_LARGE_GROUP_TESTS


@pytest.mark.parametrize("test_case", pytest_params(SUM_BOUNDARY_AND_LARGE_GROUP_TESTS))
def test_sum_boundary(collection, test_case: AccumulatorTestCase):
"""Test $sum integer boundary values and large group accumulation."""
if test_case.docs:
collection.insert_many(test_case.docs)
result = execute_command(
collection,
{"aggregate": collection.name, "pipeline": test_case.pipeline or [], "cursor": {}},
)
assertSuccess(
result,
[test_case.expected],
msg=test_case.msg,
)


# Property [Negative Zero Normalization]: $sum normalizes negative zero to
# positive zero for both double and Decimal128.
SUM_NEGATIVE_ZERO_TESTS: list[AccumulatorTestCase] = [
AccumulatorTestCase(
"neg_zero_double_single",
docs=[{"v": DOUBLE_NEGATIVE_ZERO}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "str": {"$toString": "$result"}}},
],
expected="0",
msg="$sum should normalize a single double -0.0 to +0.0",
),
AccumulatorTestCase(
"neg_zero_double_sum",
docs=[{"v": DOUBLE_NEGATIVE_ZERO}, {"v": DOUBLE_NEGATIVE_ZERO}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "str": {"$toString": "$result"}}},
],
expected="0",
msg="$sum should normalize -0.0 + -0.0 to +0.0",
),
AccumulatorTestCase(
"neg_zero_decimal128_single",
docs=[{"v": DECIMAL128_NEGATIVE_ZERO}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "str": {"$toString": "$result"}}},
],
expected="0",
msg="$sum should normalize a single Decimal128('-0') to Decimal128('0')",
),
AccumulatorTestCase(
"neg_zero_decimal128_sum",
docs=[{"v": DECIMAL128_NEGATIVE_ZERO}, {"v": DECIMAL128_NEGATIVE_ZERO}],
pipeline=[
{"$group": {"_id": None, "result": {"$sum": "$v"}}},
{"$project": {"_id": 0, "str": {"$toString": "$result"}}},
],
expected="0",
msg="$sum should normalize Decimal128('-0') + Decimal128('-0') to Decimal128('0')",
),
]


@pytest.mark.parametrize("test_case", pytest_params(SUM_NEGATIVE_ZERO_TESTS))
def test_sum_negative_zero(collection, test_case: AccumulatorTestCase):
"""Test $sum negative zero normalization."""
if test_case.docs:
collection.insert_many(test_case.docs)
result = execute_command(
collection,
{"aggregate": collection.name, "pipeline": test_case.pipeline or [], "cursor": {}},
)
assertSuccess(
result,
[{"str": test_case.expected}],
msg=test_case.msg,
)
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