mongodb/jstests/noPassthrough/change_streams_collation_chunk_migration.js

/**
 * Tests that a change stream on a sharded collection with a non-simple default collation is not
 * erroneously invalidated upon chunk migration. Reproduction script for the bug in SERVER-33944.
 * @tags: [requires_replication, requires_journaling]
 */
(function() {
    load("jstests/libs/collection_drop_recreate.js");  // For assert[Drop|Create]Collection.
    load("jstests/libs/change_stream_util.js");        // For 'ChangeStreamTest'.

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

    const testDB = st.s.getDB(jsTestName());

    // Enable sharding on the test database and ensure that the primary is shard0.
    assert.commandWorked(testDB.adminCommand({enableSharding: testDB.getName()}));
    st.ensurePrimaryShard(testDB.getName(), st.shard0.shardName);

    const caseInsensitiveCollectionName = "change_stream_case_insensitive";
    const caseInsensitive = {locale: "en_US", strength: 2};

    // Create the collection with a case-insensitive collation, then shard it on {shardKey: 1}.
    const caseInsensitiveCollection = assertDropAndRecreateCollection(
        testDB, caseInsensitiveCollectionName, {collation: caseInsensitive});
    assert.commandWorked(
        caseInsensitiveCollection.createIndex({shardKey: 1}, {collation: {locale: "simple"}}));
    assert.commandWorked(testDB.adminCommand({
        shardCollection: caseInsensitiveCollection.getFullName(),
        key: {shardKey: 1},
        collation: {locale: "simple"}
    }));

    // Verify that the collection does not exist on shard1.
    assert(!st.shard1.getCollection(caseInsensitiveCollection.getFullName()).exists());

    // Now open a change stream on the collection.
    const cst = new ChangeStreamTest(testDB);
    const csCursor = cst.startWatchingChanges({
        pipeline: [{$changeStream: {}}, {$project: {docId: "$documentKey.shardKey"}}],
        collection: caseInsensitiveCollection
    });

    // Insert some documents into the collection.
    assert.commandWorked(caseInsensitiveCollection.insert({shardKey: 0, text: "aBc"}));
    assert.commandWorked(caseInsensitiveCollection.insert({shardKey: 1, text: "abc"}));

    // Move a chunk from shard0 to shard1. This will create the collection on shard1.
    assert.commandWorked(testDB.adminCommand({
        moveChunk: caseInsensitiveCollection.getFullName(),
        find: {shardKey: 1},
        to: st.rs1.getURL(),
        _waitForDelete: false
    }));

    // Attempt to read from the change stream. We should see both inserts, without an invalidation.
    cst.assertNextChangesEqual({cursor: csCursor, expectedChanges: [{docId: 0}, {docId: 1}]});

    st.stop();
})();