Tests of nodes that use config nodes that implement RED.httpAdmin.get(… fail

[jorisadri]

When testing nodes that use a config node that implements RED.httpAdmin.get(…, the tests fail.
When doing helper.getNode("node1")
It fails with this error:

TypeError: Cannot read property ‘get’ of null
at Array.module.exports  (location to line number with RED.httpAdmin.get(…  ) 
at Object.load (node_modules/node-red-node-test-helper/index.js:131:28)
at Context.<anonymous> (to location of the helper.load(<node that implements the config>))

Code of the config

module.exports = function (RED) {
    const { Account, PublicAccount, NetworkType } = require('nem2-sdk');
    function accountConfig(config) {
        RED.nodes.createNode(this, config);
        this.name = config.name;
        this.privateKey = config.privateKey;
        this.publicKey = config.publicKey;
        this.address = config.address;
        this.network = RED.nodes.getNode(config.network).network
    }
    RED.nodes.registerType("accountConfig", accountConfig);
    RED.httpAdmin.get("/accountinfo", RED.auth.needsPermission('accountConfig.read'), function (req, res) {
        const network = RED.nodes.getNode(req.query.network).network
        let publicKey = req.query.privateKey ? Account.createFromPrivateKey(req.query.privateKey, NetworkType[network]).publicKey : req.query.publicKey;
        let address = publicKey ? PublicAccount.createFromPublicKey(publicKey, NetworkType[network]).address.plain() : req.query.address;
        res.json({ publicKey: publicKey, address: address });
    });
};