40 lines
1.8 KiB
JavaScript
40 lines
1.8 KiB
JavaScript
// SERVER-20168: Add option to $unwind to output a null result for empty arrays.
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(function() {
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"use strict";
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var coll = db.server20168;
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coll.drop();
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// Should return no results on a non-existent collection.
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var results = coll.aggregate([{$unwind: {path: "$x"}}]).toArray();
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assert.eq(0, results.length, "$unwind returned the wrong number of results");
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/**
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* Asserts that with the input 'inputDoc', an $unwind stage on 'unwindPath' should produce no
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* results if preserveNullAndEmptyArrays is not specified, and produces one result, equal to
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* 'outputDoc', if it is specified.
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*/
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function testPreserveNullAndEmptyArraysParam(inputDoc, unwindPath, outputDoc) {
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coll.drop();
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assert.writeOK(coll.insert(inputDoc));
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// If preserveNullAndEmptyArrays is passed, we should get an output document.
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var preservedResults =
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coll.aggregate([{$unwind: {path: unwindPath, preserveNullAndEmptyArrays: true}}])
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.toArray();
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assert.eq(1, preservedResults.length, "$unwind returned the wrong number of results");
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assert.eq(preservedResults[0],
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outputDoc,
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"Unexpected result for an $unwind with preserveNullAndEmptyArrays " +
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"(input was " + tojson(inputDoc) + ")");
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// If not, we should get no outputs.
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var defaultResults = coll.aggregate([{$unwind: {path: unwindPath}}]).toArray();
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assert.eq(0, defaultResults.length, "$unwind returned the wrong number of results");
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}
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testPreserveNullAndEmptyArraysParam({_id: 0}, "$x", {_id: 0});
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testPreserveNullAndEmptyArraysParam({_id: 0, x: null}, "$x", {_id: 0, x: null});
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testPreserveNullAndEmptyArraysParam({_id: 0, x: []}, "$x", {_id: 0});
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}());
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