mongodb/jstests/replsets/election_handoff_basic.js

/**
 * This is a basic test that checks that, with election handoff is enabled, a primary that steps
 * down sends a ReplSetStepUp request to an eligible candidate. It uses a two-node replica set,
 * so there is only one secondary that can take over.
 */

(function() {
"use strict";
load("jstests/replsets/libs/election_handoff.js");

const testName = "election_handoff_vanilla";
const numNodes = 2;
const rst = ReplSetTest({name: testName, nodes: numNodes});
const nodes = rst.nodeList();
rst.startSet();

// Make sure there are no election timeouts firing for the duration of the test. This helps
// ensure that the test will only pass if the election handoff succeeds.
rst.initiateWithHighElectionTimeout();

ElectionHandoffTest.testElectionHandoff(rst, 0, 1);

rst.stopSet();
})();