diff --git a/benchmarks/commonUtilities.js b/benchmarks/commonUtilities.js
deleted file mode 100755
index 04d315f..0000000
--- a/benchmarks/commonUtilities.js
+++ /dev/null
@@ -1,287 +0,0 @@
-/**
- * Functions that are used in several benchmark tests
- */
-const fs = require('fs')
-const Datastore = require('../lib/datastore')
-const Persistence = require('../lib/persistence')
-const { callbackify } = require('util')
-let executeAsap
-
-try {
-  executeAsap = setImmediate
-} catch (e) {
-  executeAsap = process.nextTick
-}
-
-/**
- * Configure the benchmark
- */
-module.exports.getConfiguration = function (benchDb) {
-  const program = require('commander')
-
-  program
-    .option('-n --number [number]', 'Size of the collection to test on', parseInt)
-    .option('-i --with-index', 'Use an index')
-    .option('-m --in-memory', 'Test with an in-memory only store')
-    .parse(process.argv)
-
-  const n = program.number || 10000
-
-  console.log('----------------------------')
-  console.log('Test with ' + n + ' documents')
-  console.log(program.withIndex ? 'Use an index' : 'Don\'t use an index')
-  console.log(program.inMemory ? 'Use an in-memory datastore' : 'Use a persistent datastore')
-  console.log('----------------------------')
-
-  const d = new Datastore({
-    filename: benchDb,
-    inMemoryOnly: program.inMemory
-  })
-
-  return { n, d, program }
-}
-
-/**
- * Ensure the workspace stat and the db datafile is empty
- */
-module.exports.prepareDb = function (filename, cb) {
-  callbackify((filename) => Persistence.ensureParentDirectoryExistsAsync(filename))(filename, function () {
-    fs.access(filename, fs.constants.FS_OK, function (err) {
-      if (!err) {
-        fs.unlink(filename, cb)
-      } else { return cb() }
-    })
-  })
-}
-
-/**
- * Return an array with the numbers from 0 to n-1, in a random order
- * Uses Fisher Yates algorithm
- * Useful to get fair tests
- */
-function getRandomArray (n) {
-  const res = []
-  let i
-  let j
-  let temp
-
-  for (i = 0; i < n; i += 1) { res[i] = i }
-
-  for (i = n - 1; i >= 1; i -= 1) {
-    j = Math.floor((i + 1) * Math.random())
-    temp = res[i]
-    res[i] = res[j]
-    res[j] = temp
-  }
-
-  return res
-}
-module.exports.getRandomArray = getRandomArray
-
-/**
- * Insert a certain number of documents for testing
- */
-module.exports.insertDocs = function (d, n, profiler, cb) {
-  const order = getRandomArray(n)
-
-  profiler.step('Begin inserting ' + n + ' docs')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      const opsPerSecond = Math.floor(1000 * n / profiler.elapsedSinceLastStep())
-      console.log('===== RESULT (insert) ===== ' + opsPerSecond + ' ops/s')
-      profiler.step('Finished inserting ' + n + ' docs')
-      profiler.insertOpsPerSecond = opsPerSecond
-      return cb()
-    }
-
-    // eslint-disable-next-line n/handle-callback-err
-    d.insert({ docNumber: order[i] }, function (err) {
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Find documents with find
- */
-module.exports.findDocs = function (d, n, profiler, cb) {
-  const order = getRandomArray(n)
-
-  profiler.step('Finding ' + n + ' documents')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      console.log('===== RESULT (find) ===== ' + Math.floor(1000 * n / profiler.elapsedSinceLastStep()) + ' ops/s')
-      profiler.step('Finished finding ' + n + ' docs')
-      return cb()
-    }
-
-    // eslint-disable-next-line n/handle-callback-err
-    d.find({ docNumber: order[i] }, function (err, docs) {
-      if (docs.length !== 1 || docs[0].docNumber !== order[i]) { return cb(new Error('One find didnt work')) }
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Find documents with find and the $in operator
- */
-module.exports.findDocsWithIn = function (d, n, profiler, cb) {
-  const ins = []
-  const arraySize = Math.min(10, n)
-
-  // Preparing all the $in arrays, will take some time
-  for (let i = 0; i < n; i += 1) {
-    ins[i] = []
-
-    for (let j = 0; j < arraySize; j += 1) {
-      ins[i].push((i + j) % n)
-    }
-  }
-
-  profiler.step('Finding ' + n + ' documents WITH $IN OPERATOR')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      console.log('===== RESULT (find with in selector) ===== ' + Math.floor(1000 * n / profiler.elapsedSinceLastStep()) + ' ops/s')
-      profiler.step('Finished finding ' + n + ' docs')
-      return cb()
-    }
-
-    // eslint-disable-next-line n/handle-callback-err
-    d.find({ docNumber: { $in: ins[i] } }, function (err, docs) {
-      if (docs.length !== arraySize) { return cb(new Error('One find didnt work')) }
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Find documents with findOne
- */
-module.exports.findOneDocs = function (d, n, profiler, cb) {
-  const order = getRandomArray(n)
-
-  profiler.step('FindingOne ' + n + ' documents')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      console.log('===== RESULT (findOne) ===== ' + Math.floor(1000 * n / profiler.elapsedSinceLastStep()) + ' ops/s')
-      profiler.step('Finished finding ' + n + ' docs')
-      return cb()
-    }
-
-    // eslint-disable-next-line n/handle-callback-err
-    d.findOne({ docNumber: order[i] }, function (err, doc) {
-      if (!doc || doc.docNumber !== order[i]) { return cb(new Error('One find didnt work')) }
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Update documents
- * options is the same as the options object for update
- */
-module.exports.updateDocs = function (options, d, n, profiler, cb) {
-  const order = getRandomArray(n)
-
-  profiler.step('Updating ' + n + ' documents')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      console.log('===== RESULT (update) ===== ' + Math.floor(1000 * n / profiler.elapsedSinceLastStep()) + ' ops/s')
-      profiler.step('Finished updating ' + n + ' docs')
-      return cb()
-    }
-
-    // Will not actually modify the document but will take the same time
-    d.update({ docNumber: order[i] }, { docNumber: order[i] }, options, function (err, nr) {
-      if (err) { return cb(err) }
-      if (nr !== 1) { return cb(new Error('One update didnt work')) }
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Remove documents
- * options is the same as the options object for update
- */
-module.exports.removeDocs = function (options, d, n, profiler, cb) {
-  const order = getRandomArray(n)
-
-  profiler.step('Removing ' + n + ' documents')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      // opsPerSecond corresponds to 1 insert + 1 remove, needed to keep collection size at 10,000
-      // We need to subtract the time taken by one insert to get the time actually taken by one remove
-      const opsPerSecond = Math.floor(1000 * n / profiler.elapsedSinceLastStep())
-      const removeOpsPerSecond = Math.floor(1 / ((1 / opsPerSecond) - (1 / profiler.insertOpsPerSecond)))
-      console.log('===== RESULT (remove) ===== ' + removeOpsPerSecond + ' ops/s')
-      profiler.step('Finished removing ' + n + ' docs')
-      return cb()
-    }
-
-    d.remove({ docNumber: order[i] }, options, function (err, nr) {
-      if (err) { return cb(err) }
-      if (nr !== 1) { return cb(new Error('One remove didnt work')) }
-      // eslint-disable-next-line n/handle-callback-err
-      d.insert({ docNumber: order[i] }, function (err) { // We need to reinsert the doc so that we keep the collection's size at n
-        // So actually we're calculating the average time taken by one insert + one remove
-        executeAsap(function () {
-          runFrom(i + 1)
-        })
-      })
-    })
-  }
-
-  runFrom(0)
-}
-
-/**
- * Load database
- */
-module.exports.loadDatabase = function (d, n, profiler, cb) {
-  profiler.step('Loading the database ' + n + ' times')
-
-  function runFrom (i) {
-    if (i === n) { // Finished
-      console.log('===== RESULT ===== ' + Math.floor(1000 * n / profiler.elapsedSinceLastStep()) + ' ops/s')
-      profiler.step('Finished loading a database' + n + ' times')
-      return cb()
-    }
-
-    // eslint-disable-next-line n/handle-callback-err
-    d.loadDatabase(function (err) {
-      executeAsap(function () {
-        runFrom(i + 1)
-      })
-    })
-  }
-
-  runFrom(0)
-}
diff --git a/benchmarks/ensureIndex.js b/benchmarks/ensureIndex.js
deleted file mode 100755
index cf33c16..0000000
--- a/benchmarks/ensureIndex.js
+++ /dev/null
@@ -1,50 +0,0 @@
-const program = require('commander')
-const { apply, waterfall } = require('../test/utils.test.js')
-const Datastore = require('../lib/datastore')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const profiler = new Profiler('INSERT BENCH')
-const benchDb = 'workspace/insert.bench.db'
-const d = new Datastore(benchDb)
-
-program
-  .option('-n --number [number]', 'Size of the collection to test on', parseInt)
-  .option('-i --with-index', 'Test with an index')
-  .parse(process.argv)
-
-const n = program.number || 10000
-
-console.log('----------------------------')
-console.log('Test with ' + n + ' documents')
-console.log('----------------------------')
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  function (cb) {
-    let i
-
-    profiler.step('Begin calling ensureIndex ' + n + ' times')
-
-    for (i = 0; i < n; i += 1) {
-      d.ensureIndex({ fieldName: 'docNumber' })
-      delete d.indexes.docNumber
-    }
-
-    console.log('Average time for one ensureIndex: ' + (profiler.elapsedSinceLastStep() / n) + 'ms')
-    profiler.step('Finished calling ensureIndex ' + n + ' times')
-    cb()
-  }
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/find.js b/benchmarks/find.js
deleted file mode 100755
index d3c9a83..0000000
--- a/benchmarks/find.js
+++ /dev/null
@@ -1,27 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const profiler = new Profiler('FIND BENCH')
-const benchDb = 'workspace/find.bench.db'
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-const n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) { d.ensureIndex({ fieldName: 'docNumber' }) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  apply(commonUtilities.findDocs, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/findOne.js b/benchmarks/findOne.js
deleted file mode 100755
index b965709..0000000
--- a/benchmarks/findOne.js
+++ /dev/null
@@ -1,28 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/findOne.bench.db'
-const profiler = new Profiler('FINDONE BENCH')
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-const n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) { d.ensureIndex({ fieldName: 'docNumber' }) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  function (cb) { setTimeout(function () { cb() }, 500) },
-  apply(commonUtilities.findOneDocs, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/findWithIn.js b/benchmarks/findWithIn.js
deleted file mode 100755
index 8df0c41..0000000
--- a/benchmarks/findWithIn.js
+++ /dev/null
@@ -1,27 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/find.bench.db'
-const profiler = new Profiler('FIND BENCH')
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-const n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) { d.ensureIndex({ fieldName: 'docNumber' }) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  apply(commonUtilities.findDocsWithIn, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/insert.js b/benchmarks/insert.js
deleted file mode 100755
index 4938212..0000000
--- a/benchmarks/insert.js
+++ /dev/null
@@ -1,32 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/insert.bench.db'
-const profiler = new Profiler('INSERT BENCH')
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-let n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) {
-        d.ensureIndex({ fieldName: 'docNumber' })
-        n = 2 * n // We will actually insert twice as many documents
-        // because the index is slower when the collection is already
-        // big. So the result given by the algorithm will be a bit worse than
-        // actual performance
-      }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/loadDatabase.js b/benchmarks/loadDatabase.js
deleted file mode 100755
index b007dfb..0000000
--- a/benchmarks/loadDatabase.js
+++ /dev/null
@@ -1,35 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const program = require('commander')
-const Datastore = require('../lib/datastore')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/loaddb.bench.db'
-const profiler = new Profiler('LOADDB BENCH')
-const d = new Datastore(benchDb)
-
-program
-  .option('-n --number [number]', 'Size of the collection to test on', parseInt)
-  .option('-i --with-index', 'Test with an index')
-  .parse(process.argv)
-
-const n = program.number || 10000
-
-console.log('----------------------------')
-console.log('Test with ' + n + ' documents')
-console.log(program.withIndex ? 'Use an index' : "Don't use an index")
-console.log('----------------------------')
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(cb)
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  apply(commonUtilities.loadDatabase, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/profiler.js b/benchmarks/profiler.js
deleted file mode 100644
index a5d73af..0000000
--- a/benchmarks/profiler.js
+++ /dev/null
@@ -1,92 +0,0 @@
-const util = require('util')
-
-function formatTime (time, precision) {
-  // If we're dealing with ms, round up to seconds when time is at least 1 second
-  if (time > 1000 && precision === 'ms') {
-    return (Math.floor(time / 100) / 10) + ' s'
-  } else {
-    return time.toFixed(3) + ' ' + precision
-  }
-}
-
-// get time in ns
-function getTime () {
-  const t = process.hrtime()
-  return (t[0] * 1e9 + t[1])
-}
-
-/**
- * Create a profiler with name testName to monitor the execution time of a route
- * The profiler has two arguments: a step msg and an optional reset for the internal timer
- * It will display the execution time per step and total from latest rest
- *
- * Optional logToConsole flag, which defaults to true, causes steps to be printed to console.
- * otherwise, they can be accessed from Profiler.steps array.
- */
-function Profiler (name, logToConsole, precision) {
-  this.name = name
-  this.steps = []
-  this.sinceBeginning = null
-  this.lastStep = null
-  this.logToConsole = typeof (logToConsole) === 'undefined' ? true : logToConsole
-  this.precision = typeof (precision) === 'undefined' ? 'ms' : precision
-  this.divisor = 1
-
-  if (this.precision === 'ms') this.divisor = 1e6
-}
-
-Profiler.prototype.beginProfiling = function () {
-  if (this.logToConsole) { console.log(this.name + ' - Begin profiling') }
-  this.resetTimers()
-}
-
-Profiler.prototype.resetTimers = function () {
-  this.sinceBeginning = getTime()
-  this.lastStep = getTime()
-  this.steps.push(['BEGIN_TIMER', this.lastStep])
-}
-
-Profiler.prototype.elapsedSinceBeginning = function () {
-  return (getTime() - this.sinceBeginning) / this.divisor
-}
-
-Profiler.prototype.elapsedSinceLastStep = function () {
-  return (getTime() - this.lastStep) / this.divisor
-}
-
-// Return the deltas between steps, in nanoseconds
-
-Profiler.prototype.getSteps = function () {
-  const divisor = this.divisor
-
-  return this.steps.map(function (curr, index, arr) {
-    if (index === 0) return undefined
-    const delta = (curr[1] - arr[index - 1][1])
-    return [curr[0], (delta / divisor)]
-  }).slice(1)
-}
-
-Profiler.prototype.step = function (msg) {
-  if (!this.sinceBeginning || !this.lastStep) {
-    console.log(util.format(
-      '%s - %s - You must call beginProfiling before registering steps',
-      this.name,
-      msg
-    ))
-    return
-  }
-
-  if (this.logToConsole) {
-    console.log(util.format('%s - %s - %s (total: %s)',
-      this.name,
-      msg,
-      formatTime(this.elapsedSinceLastStep(), this.precision),
-      formatTime(this.elapsedSinceBeginning(), this.precision)
-    ))
-  }
-
-  this.lastStep = getTime()
-  this.steps.push([msg, this.lastStep])
-}
-
-module.exports = Profiler
diff --git a/benchmarks/remove.js b/benchmarks/remove.js
deleted file mode 100755
index e3607f2..0000000
--- a/benchmarks/remove.js
+++ /dev/null
@@ -1,35 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/remove.bench.db'
-const profiler = new Profiler('REMOVE BENCH')
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-const n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) { d.ensureIndex({ fieldName: 'docNumber' }) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-
-  // Test with remove only one document
-  function (cb) { profiler.step('MULTI: FALSE'); return cb() },
-  apply(commonUtilities.removeDocs, { multi: false }, d, n, profiler),
-  // Test with multiple documents
-  function (cb) { d.remove({}, { multi: true }, function () { return cb() }) },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  function (cb) { profiler.step('MULTI: TRUE'); return cb() },
-  apply(commonUtilities.removeDocs, { multi: true }, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/benchmarks/update.js b/benchmarks/update.js
deleted file mode 100755
index 3fce526..0000000
--- a/benchmarks/update.js
+++ /dev/null
@@ -1,37 +0,0 @@
-const { apply, waterfall } = require('../test/utils.test.js')
-const commonUtilities = require('./commonUtilities')
-const Profiler = require('./profiler')
-
-const benchDb = 'workspace/update.bench.db'
-const profiler = new Profiler('UPDATE BENCH')
-const config = commonUtilities.getConfiguration(benchDb)
-const d = config.d
-const n = config.n
-
-waterfall([
-  apply(commonUtilities.prepareDb, benchDb),
-  function (cb) {
-    d.loadDatabase(function (err) {
-      if (err) { return cb(err) }
-      if (config.program.withIndex) { d.ensureIndex({ fieldName: 'docNumber' }) }
-      cb()
-    })
-  },
-  function (cb) { profiler.beginProfiling(); return cb() },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-
-  // Test with update only one document
-  function (cb) { profiler.step('MULTI: FALSE'); return cb() },
-  apply(commonUtilities.updateDocs, { multi: false }, d, n, profiler),
-
-  // Test with multiple documents
-  // eslint-disable-next-line n/handle-callback-err
-  function (cb) { d.remove({}, { multi: true }, function (err) { return cb() }) },
-  apply(commonUtilities.insertDocs, d, n, profiler),
-  function (cb) { profiler.step('MULTI: TRUE'); return cb() },
-  apply(commonUtilities.updateDocs, { multi: true }, d, n, profiler)
-], function (err) {
-  profiler.step('Benchmark finished')
-
-  if (err) { return console.log('An error was encountered: ', err) }
-})
diff --git a/test/benchmark.test.js b/test/benchmark.test.js
new file mode 100644
index 0000000..14fd963
--- /dev/null
+++ b/test/benchmark.test.js
@@ -0,0 +1,292 @@
+import { promisify } from 'util'
+import { performance } from 'node:perf_hooks'
+import Persistence from '../src/persistence.js'
+import { access, unlink, constants } from 'fs/promises'
+import Datastore from '../src/datastore.js'
+
+const getRandomArray = n => {
+  const res = []
+  let i
+  let j
+  let temp
+
+  for (i = 0; i < n; i += 1) { res[i] = i }
+
+  for (i = n - 1; i >= 1; i -= 1) {
+    j = Math.floor((i + 1) * Math.random())
+    temp = res[i]
+    res[i] = res[j]
+    res[j] = temp
+  }
+
+  return res
+}
+
+const insertDocs = async (d, n) => {
+  const order = getRandomArray(n)
+
+  for (let i = 0; i <= n; i++) {
+    await d.insertAsync({ docNumber: order[i] })
+    await promisify(process.nextTick)()
+  }
+}
+
+const measure = async (name, n, cb) => {
+  performance.mark(`${name} start`)
+
+  for (let i = 0; i < n; i += 1) {
+    await cb(i)
+  }
+
+  performance.mark(`${name} end`)
+
+  const { duration } = performance.measure(`${name} average duration for ${n} operations`, `${name} start`, `${name} end`)
+  const opsPerSecond = Math.floor(1000 * n / duration)
+
+  console.log(`===== RESULT (${name}) ===== ${opsPerSecond} ops/s ===== ${Math.floor(duration / n * 1000) / 1000}ms/execution`)
+}
+
+describe('Performance tests without index', function () {
+  const n = 1000
+  const benchDb = 'workspace/bench.db'
+  let d
+
+  before(function () {
+    if (!process.argv.includes('--benchmark')) this.skip()
+    else this.timeout(60000)
+  })
+
+  beforeEach('Prepare database', async () => {
+    try {
+      await access(benchDb, constants.F_OK)
+      await unlink(benchDb)
+    } catch {}
+    await Persistence.ensureParentDirectoryExistsAsync(benchDb)
+    d = new Datastore({ filename: benchDb })
+    await d.loadDatabaseAsync()
+  })
+
+  afterEach('Clean database', async () => {
+    try {
+      await d.this.executor.queue.guardian
+      d = null
+      await access(benchDb, constants.F_OK)
+      await unlink(benchDb)
+    } catch {}
+  })
+
+  it('ensureIndex', async () => {
+    await insertDocs(d, n)
+    await measure('ensureIndex', n, async (i) => {
+      d.ensureIndexAsync({ fieldName: 'docNumber' })
+      delete d.indexes.docNumber
+    })
+  })
+
+  it('find', async () => {
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('find', n, async (i) => {
+      const docs = await d.findAsync({ docNumber: order[i] })
+      if (docs.length !== 1 || docs[0].docNumber !== order[i]) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('findOne', async () => {
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('findOne', n, async (i) => {
+      const doc = await d.findOneAsync({ docNumber: order[i] })
+      if (doc == null || doc.docNumber !== order[i]) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('find with $in', async () => {
+    await insertDocs(d, n)
+
+    const ins = []
+    const arraySize = Math.min(10, n)
+
+    // Preparing all the $in arrays, will take some time
+    for (let i = 0; i < n; i += 1) {
+      ins[i] = []
+
+      for (let j = 0; j < arraySize; j += 1) {
+        ins[i].push((i + j) % n)
+      }
+    }
+
+    await measure('find with $in', n, async (i) => {
+      const docs = await d.findAsync({ docNumber: { $in: ins[i] } })
+      if (docs.length !== arraySize) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('insert docs', async () => {
+    const order = getRandomArray(n)
+    await measure('insert docs', n, async (i) => {
+      await d.insertAsync({ docNumber: order[i] })
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('load database', async () => {
+    await insertDocs(d, n)
+    await measure('load database', n, async (i) => {
+      await d.loadDatabaseAsync()
+    })
+  })
+
+  it('Insert and remove one', async () => {
+    // TODO measure only remove
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one', n, async (i) => {
+      const nr = await d.removeAsync({ docNumber: order[i] }, { multi: false })
+      if (nr !== 1) throw new Error('One remove didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Insert and remove one with multi option', async () => {
+    // TODO measure only remove
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option', n, async (i) => {
+      const nr = await d.removeAsync({ docNumber: order[i] }, { multi: true })
+      if (nr !== 1) throw new Error('One remove didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Update', async () => {
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option', n, async (i) => {
+      const { numAffected } = await d.updateAsync({ docNumber: order[i] }, { docNumber: order[i] }, { multi: false })
+      if (numAffected !== 1) throw new Error('One update didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Update with multi option', async () => {
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option', n, async (i) => {
+      const { numAffected } = await d.updateAsync({ docNumber: order[i] }, { docNumber: order[i] }, { multi: true })
+      if (numAffected !== 1) throw new Error('One update didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('find with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('find with index', n, async (i) => {
+      const docs = await d.findAsync({ docNumber: order[i] })
+      if (docs.length !== 1 || docs[0].docNumber !== order[i]) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('findOne with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('findOne with index', n, async (i) => {
+      const doc = await d.findOneAsync({ docNumber: order[i] })
+      if (doc == null || doc.docNumber !== order[i]) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('find with $in with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+
+    const ins = []
+    const arraySize = Math.min(10, n)
+
+    // Preparing all the $in arrays, will take some time
+    for (let i = 0; i < n; i += 1) {
+      ins[i] = []
+
+      for (let j = 0; j < arraySize; j += 1) {
+        ins[i].push((i + j) % n)
+      }
+    }
+
+    await measure('find with $in with index', n, async (i) => {
+      const docs = await d.findAsync({ docNumber: { $in: ins[i] } })
+      if (docs.length !== arraySize) throw new Error('One find didnt work')
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('insert docs with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    const order = getRandomArray(n)
+    await measure('insert docs with index', n, async (i) => {
+      await d.insertAsync({ docNumber: order[i] })
+      await promisify(process.nextTick)()
+    })
+  })
+
+  it('load database with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    await measure('load database with index', n, async (i) => {
+      await d.loadDatabaseAsync()
+    })
+  })
+
+  it('Insert and remove one with index', async () => {
+    // TODO measure only remove
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with index', n, async (i) => {
+      const nr = await d.removeAsync({ docNumber: order[i] }, { multi: false })
+      if (nr !== 1) throw new Error('One remove didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Insert and remove one with multi option with index', async () => {
+    // TODO measure only remove
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option with index', n, async (i) => {
+      const nr = await d.removeAsync({ docNumber: order[i] }, { multi: true })
+      if (nr !== 1) throw new Error('One remove didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Update with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option with index', n, async (i) => {
+      const { numAffected } = await d.updateAsync({ docNumber: order[i] }, { docNumber: order[i] }, { multi: false })
+      if (numAffected !== 1) throw new Error('One update didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+
+  it('Update with multi option with index', async () => {
+    await d.ensureIndexAsync({ fieldName: 'docNumber' })
+    await insertDocs(d, n)
+    const order = getRandomArray(n)
+    await measure('insert and remove one with multi option with index', n, async (i) => {
+      const { numAffected } = await d.updateAsync({ docNumber: order[i] }, { docNumber: order[i] }, { multi: true })
+      if (numAffected !== 1) throw new Error('One update didnt work')
+      await d.insertAsync({ docNumber: order[i] })
+    })
+  })
+})