mongo/jstests/aggregation/accumulators/bucketAuto_push.js

87 lines
2.7 KiB
JavaScript

/**
* Tests that $push under $bucketAuto preserves incoming document order.
*/
const coll = db[jsTestName()];
coll.drop();
const docs = [];
for (let i = 0; i < 10; i++) {
docs.push({_id: i, n: 9 - i});
}
coll.insertMany(docs);
{
// One bucket, all the documents coming out of the $bucketAuto stage should be in the same
// order as they came in (i.e. sorted by _id).
const res = coll
.aggregate([{$sort: {_id: 1}}, {$bucketAuto: {groupBy: "$n", buckets: 1, output: {docs: {$push: "$$ROOT"}}}}])
.toArray();
const expected = [
{
"_id": {"min": 0, "max": 9},
"docs": [
{"_id": 0, "n": 9},
{"_id": 1, "n": 8},
{"_id": 2, "n": 7},
{"_id": 3, "n": 6},
{"_id": 4, "n": 5},
{"_id": 5, "n": 4},
{"_id": 6, "n": 3},
{"_id": 7, "n": 2},
{"_id": 8, "n": 1},
{"_id": 9, "n": 0},
],
},
];
assert.eq(res, expected, "$bucketAuto with 1 bucket & $push does not obey sort order of incoming docs.");
}
{
// Two buckets, the documents in each bucket should be sorted by _id as well.
const res = coll
.aggregate([{$sort: {_id: 1}}, {$bucketAuto: {groupBy: "$n", buckets: 2, output: {docs: {$push: "$$ROOT"}}}}])
.toArray();
const expected = [
{
"_id": {"min": 0, "max": 5},
"docs": [
{"_id": 5, "n": 4},
{"_id": 6, "n": 3},
{"_id": 7, "n": 2},
{"_id": 8, "n": 1},
{"_id": 9, "n": 0},
],
},
{
"_id": {"min": 5, "max": 9},
"docs": [
{"_id": 0, "n": 9},
{"_id": 1, "n": 8},
{"_id": 2, "n": 7},
{"_id": 3, "n": 6},
{"_id": 4, "n": 5},
],
},
];
assert.eq(res, expected, "$bucketAuto with 2 buckets & $push does not obey sort order of incoming docs.");
}
{
// Ensure that if we try to $push something that evaluates to 'missing', no value gets pushed to
// the resulting array.
const res = coll
.aggregate([
{
"$bucketAuto": {
"groupBy": "$a",
"buckets": 1,
"output": {"array": {"$push": {$getField: {"field": "b", "input": {a: 0}}}}},
},
},
])
.toArray();
const expected = [{"_id": {"min": null, "max": null}, "array": []}];
assert.eq(res, expected, "$bucketAuto with $push does not push any missing values as null.");
}