mongo/jstests/core/mr_replaceIntoDB.js

t = db.mr_replace;
t.drop();

t.insert({a: [1, 2]});
t.insert({a: [2, 3]});
t.insert({a: [3, 4]});

outCollStr = "mr_replace_col";
outDbStr = "mr_db";

m = function() {
    for (i = 0; i < this.a.length; i++)
        emit(this.a[i], 1);
};
r = function(k, vs) {
    return Array.sum(vs);
};

function tos(o) {
    var s = "";
    for (var i = 0; i < 100; i++) {
        if (o[i])
            s += i + "_" + o[i];
    }
    return s;
}

print("Testing mr replace into other DB");
res = t.mapReduce(m, r, {out: {replace: outCollStr, db: outDbStr}});
printjson(res);
expected = {
    "1": 1,
    "2": 2,
    "3": 2,
    "4": 1
};
outDb = db.getMongo().getDB(outDbStr);
outColl = outDb[outCollStr];
str = tos(outColl.convertToSingleObject("value"));
print("Received result: " + str);
assert.eq(tos(expected), str, "A Received wrong result " + str);

print("checking result field");
assert.eq(res.result.collection, outCollStr, "B1 Wrong collection " + res.result.collection);
assert.eq(res.result.db, outDbStr, "B2 Wrong db " + res.result.db);

print("Replace again and check");
outColl.save({_id: "5", value: 1});
t.mapReduce(m, r, {out: {replace: outCollStr, db: outDbStr}});
str = tos(outColl.convertToSingleObject("value"));
print("Received result: " + str);
assert.eq(tos(expected), str, "C1 Received wrong result " + str);