// Change a write concern mode from 2 to 3 servers

var host = getHostName();
var replTest = new ReplSetTest({name: "rstag", nodes: 4});
var nodes = replTest.startSet();
var ports = replTest.ports;
var conf = {
    _id: "rstag",
    version: 1,
    members: [
        {_id: 0, host: host + ":" + ports[0], tags: {"backup": "A"}},
        {_id: 1, host: host + ":" + ports[1], tags: {"backup": "B"}},
        {_id: 2, host: host + ":" + ports[2], tags: {"backup": "C"}},
        {_id: 3, host: host + ":" + ports[3], tags: {"backup": "D"}, arbiterOnly: true}
    ],
    settings: {getLastErrorModes: {backedUp: {backup: 2}}}
};

print("arbiters can't have tags");
var result = nodes[0].getDB("admin").runCommand({replSetInitiate: conf});
printjson(result);
assert.eq(result.ok, 0);

conf.members.pop();
replTest.stop(3);
replTest.remove(3);
replTest.initiate(conf);

replTest.awaitReplication();

master = replTest.getPrimary();
var db = master.getDB("test");
assert.writeOK(db.foo.insert({x: 1}, {writeConcern: {w: 'backedUp', wtimeout: 20000}}));

conf.version = 2;
conf.settings.getLastErrorModes.backedUp.backup = 3;
master.getDB("admin").runCommand({replSetReconfig: conf});
replTest.awaitReplication();

master = replTest.getPrimary();
var db = master.getDB("test");
assert.writeOK(db.foo.insert({x: 2}, {writeConcern: {w: 'backedUp', wtimeout: 20000}}));

conf.version = 3;
conf.members[0].priorty = 3;
conf.members[2].priorty = 0;
master.getDB("admin").runCommand({replSetReconfig: conf});

master = replTest.getPrimary();
var db = master.getDB("test");
assert.writeOK(db.foo.insert({x: 3}, {writeConcern: {w: 'backedUp', wtimeout: 20000}}));

replTest.stopSet();