mongodb/jstests/noPassthrough/feature_compatibility_version.js

// Tests that manipulating the featureCompatibilityVersion document in admin.system.version changes
// the value of the featureCompatibilityVersion server parameter.

(function() {
    "use strict";

    load("jstests/libs/feature_compatibility_version.js");

    const conn = MongoRunner.runMongod({});
    assert.neq(null, conn, "mongod was unable to start up");

    let adminDB = conn.getDB("admin");

    // Initially the featureCompatibilityVersion is latestFCV.
    checkFCV(adminDB, latestFCV);

    // Updating the featureCompatibilityVersion document changes the featureCompatibilityVersion
    // server parameter.
    assert.writeOK(adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                                 {$set: {version: lastStableFCV}}));
    checkFCV(adminDB, lastStableFCV);

    assert.writeOK(
        adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                      {$set: {version: lastStableFCV, targetVersion: latestFCV}}));
    checkFCV(adminDB, lastStableFCV, latestFCV);

    assert.writeOK(adminDB.system.version.update(
        {_id: "featureCompatibilityVersion"},
        {$set: {version: lastStableFCV, targetVersion: lastStableFCV}}));
    checkFCV(adminDB, lastStableFCV, lastStableFCV);

    assert.writeOK(
        adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                      {$set: {version: latestFCV}, $unset: {targetVersion: true}}));
    checkFCV(adminDB, latestFCV);

    // Updating the featureCompatibilityVersion document with an invalid version fails.
    assert.writeErrorWithCode(adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                                            {$set: {version: "3.2"}}),
                              ErrorCodes.BadValue);
    checkFCV(adminDB, latestFCV);

    // Updating the featureCompatibilityVersion document with an invalid targetVersion fails.
    assert.writeErrorWithCode(adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                                            {$set: {targetVersion: lastStableFCV}}),
                              ErrorCodes.BadValue);
    checkFCV(adminDB, latestFCV);

    assert.writeErrorWithCode(adminDB.system.version.update({_id: "featureCompatibilityVersion"},
                                                            {$set: {targetVersion: latestFCV}}),
                              ErrorCodes.BadValue);
    checkFCV(adminDB, latestFCV);

    MongoRunner.stopMongod(conn);
}());