/**
 * Perform basic tests for the mergeChunks command against mongos.
 */
(function() {
'use strict';

var st = new ShardingTest({mongos: 2, shards: 2, other: {chunkSize: 1}});
var mongos = st.s0;

var kDbName = 'db';

var shard0 = st.shard0.shardName;
var shard1 = st.shard1.shardName;

var ns = kDbName + ".foo";

assert.commandWorked(mongos.adminCommand({enableSharding: kDbName}));
st.ensurePrimaryShard(kDbName, shard0);

// Fail if invalid namespace.
assert.commandFailed(mongos.adminCommand({mergeChunks: '', bounds: [{a: -1}, {a: 1}]}));

// Fail if database does not exist.
assert.commandFailed(mongos.adminCommand({mergeChunks: 'a.b', bounds: [{a: -1}, {a: 1}]}));

// Fail if collection is unsharded.
assert.commandFailed(
    mongos.adminCommand({mergeChunks: kDbName + '.xxx', bounds: [{a: -1}, {a: 1}]}));

// Errors if either bounds is not a valid shard key.
assert.eq(0, mongos.getDB('config').chunks.count({ns: ns}));

assert.commandWorked(mongos.adminCommand({shardCollection: ns, key: {a: 1}}));
assert.eq(1, mongos.getDB('config').chunks.count({ns: ns}));
assert.commandWorked(mongos.adminCommand({split: ns, middle: {a: 0}}));
assert.commandWorked(mongos.adminCommand({split: ns, middle: {a: -1}}));
assert.commandWorked(mongos.adminCommand({split: ns, middle: {a: 1}}));

// Fail if a wrong key
assert.commandFailed(mongos.adminCommand({mergeChunks: ns, bounds: [{x: -1}, {a: 1}]}));
assert.commandFailed(mongos.adminCommand({mergeChunks: ns, bounds: [{a: -1}, {x: 1}]}));

// Fail if chunks do not contain a bound
assert.commandFailed(mongos.adminCommand({mergeChunks: ns, bounds: [{a: -1}, {a: 10}]}));

// Fail if chunks to be merged are not contiguous on the shard
assert.commandWorked(st.s0.adminCommand(
    {moveChunk: ns, bounds: [{a: -1}, {a: 0}], to: shard1, _waitForDelete: true}));
assert.commandFailed(st.s0.adminCommand({mergeChunks: ns, bounds: [{a: MinKey()}, {a: MaxKey()}]}));
assert.commandWorked(st.s0.adminCommand(
    {moveChunk: ns, bounds: [{a: -1}, {a: 0}], to: shard0, _waitForDelete: true}));

// Validate metadata
// There are four chunks [{$minKey, -1}, {-1, 0}, {0, 1}, {1, $maxKey}]
assert.eq(4, st.s0.getDB('config').chunks.count({ns: ns}));

// Use the second (stale) mongos to invoke the mergeChunks command so we can exercise the stale
// shard version refresh logic
assert.commandWorked(st.s1.adminCommand({mergeChunks: ns, bounds: [{a: -1}, {a: 1}]}));
assert.eq(3, mongos.getDB('config').chunks.count({ns: ns}));
assert.eq(1, mongos.getDB('config').chunks.count({ns: ns, min: {a: -1}, max: {a: 1}}));

st.stop();
})();