read_concern_helper.js

// This tests readConcern handling for the find/findOne shell helpers It runs find commands that
// should fail without --enableMajorityReadConcern enabled and then reruns the find commands with
// that option enabled.
(function() {
"use strict";
var testServer = MongoRunner.runMongod();
if (!testServer.getDB('admin').serverStatus().storageEngine.supportsCommittedReads) {
    jsTest.log("skipping test since storage engine doesn't support committed reads");
    MongoRunner.stopMongod(testServer);
    return;
}
var coll = testServer.getDB("test").readMajority;

assert.writeOK(coll.insert({_id: "foo"}));
assert.throws(function() { coll.find({_id: "foo"}).readConcern("majority").itcount(); });
assert.throws(function() { coll.findOne({_id: "foo"}, {}, {}, "majority"); });
assert.throws(function() { coll.count({_id: "foo"}, {readConcern: "majority"}); });
assert.throws(function() { coll.find({_id: "foo"}).readConcern("majority").count(); });

MongoRunner.stopMongod(testServer);
testServer = MongoRunner.runMongod({
    restart: true,
    port: testServer.port,
    enableMajorityReadConcern: "",
});
coll = testServer.getDB("test").readMajority;

assert.doesNotThrow(function() { coll.find({_id: "foo"}).readConcern("majority").itcount(); });
assert.doesNotThrow(function() { coll.findOne({_id: "foo"}, {}, {}, "majority"); });
assert.doesNotThrow(function() { coll.count({_id: "foo"}, {readConcern: "majority"}); });
assert.doesNotThrow(function() { coll.find({_id: "foo"}).readConcern("majority").count(); });

MongoRunner.stopMongod(testServer);
}());