Integration test for server

I have server that should perform some job before start, and log about success. For example:

const http = require('http');

function startServer() {
    const server = http.createServer((req, res) => {
        res.write('hello\n');
        res.end();
    }).listen(3000);
    console.log('server is ready');
}

//as 'job' we will use timer
setTimeout(startServer, 10000);

I need create integration tests that will check:

1. log contains information about server is ready
2. request/response work correct

Questions:

• Should I run server for every test case or enough single instance?
• Job before start server takes some time. How I know when need send request? I cannot rely on log since in this case second test will dependent on result of first one.