mongodb/jstests/sharding/unsharded_collection_targetting.js

// Tests that a stale mongos would route writes correctly to the right shard after
// an unsharded collection was moved to another shard.
import {ShardingTest} from "jstests/libs/shardingtest.js";
import {
    moveDatabaseAndUnshardedColls
} from "jstests/sharding/libs/move_database_and_unsharded_coll_helper.js";

const st = new ShardingTest({
    shards: 2,
    mongos: 2,
    rs: {
        nodes: 1,
    },
});

const testName = 'test';
const mongosDB = st.s0.getDB(testName);

// Ensure that shard1 is the primary shard.
assert.commandWorked(
    mongosDB.adminCommand({enableSharding: mongosDB.getName(), primaryShard: st.rs1.getURL()}));

// Before moving the collection, issue a write through mongos2 to make it aware
// about the location of the collection before the move.
const mongos2DB = st.s1.getDB(testName);
const mongos2Coll = mongos2DB[testName];
assert.commandWorked(mongos2Coll.insert({_id: 0, a: 0}));

moveDatabaseAndUnshardedColls(mongosDB, st.shard0.shardName);

assert.commandWorked(mongos2Coll.insert({_id: 1, a: 0}));

st.stop();