pg-pool/test/sizing.js

const expect = require('expect.js')
const co = require('co')
const _ = require('lodash')

const describe = require('mocha').describe
const it = require('mocha').it

const Pool = require('../')

describe('pool size of 1', () => {
  it('can create a single client and use it once', co.wrap(function * () {
    const pool = new Pool({ max: 1 })
    expect(pool.waitingCount).to.equal(0)
    const client = yield pool.connect()
    const res = yield client.query('SELECT $1::text as name', ['hi'])
    expect(res.rows[0].name).to.equal('hi')
    client.release()
    pool.end()
  }))

  it('can create a single client and use it multiple times', co.wrap(function * () {
    const pool = new Pool({ max: 1 })
    expect(pool.waitingCount).to.equal(0)
    const client = yield pool.connect()
    const wait = pool.connect()
    expect(pool.waitingCount).to.equal(1)
    client.release()
    const client2 = yield wait
    expect(client).to.equal(client2)
    client2.release()
    return yield pool.end()
  }))

  it('can only send 1 query at a time', co.wrap(function * () {
    const pool = new Pool({ max: 1 })

    // the query text column name changed in PostgreSQL 9.2
    const versionResult = yield pool.query('SHOW server_version_num')
    const version = parseInt(versionResult.rows[0].server_version_num, 10)
    const queryColumn = version < 90200 ? 'current_query' : 'query'

    const queryText = 'SELECT COUNT(*) as counts FROM pg_stat_activity WHERE ' + queryColumn + ' = $1'
    const queries = _.times(20, () =>
      pool.query(queryText, [queryText]))
    const results = yield Promise.all(queries)
    const counts = results.map(res => parseInt(res.rows[0].counts, 10))
    expect(counts).to.eql(_.times(20, i => 1))
    return yield pool.end()
  }))
})