node-postgres/packages/pg-pool/test/connection-strings.js

const expect = require('expect.js')
const describe = require('mocha').describe
const it = require('mocha').it
const Pool = require('../')

describe('Connection strings', function() {
  it('pool delegates connectionString property to client', function(done) {
    const connectionString = 'postgres://foo:bar@baz:1234/xur'

    const pool = new Pool({
      // use a fake client so we can check we're passed the connectionString
      Client: function(args) {
        expect(args.connectionString).to.equal(connectionString)
        return {
          connect: function(cb) {
            cb(new Error('testing'))
          },
          on: function() {},
        }
      },
      connectionString: connectionString,
    })

    pool.connect(function(err, client) {
      expect(err).to.not.be(undefined)
      done()
    })
  })
})