diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e24a7b2..8cfbf38 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        php: [7.0, 7.1, 7.2, 7.3, 7.4, 8.0]
+        php: [7.1, 7.2, 7.3, 7.4, 8.0]
 
     steps:
     - name: Checkout code
diff --git a/composer.json b/composer.json
index 438ecf5..51f141e 100644
--- a/composer.json
+++ b/composer.json
@@ -1,25 +1,26 @@
 {
-    "name":"codeception/module-mongodb",
-    "description":"MongoDB module for Codeception",
-    "keywords":["codeception", "mongodb"],
-    "homepage":"http://codeception.com/",
-    "type":"library",
-    "license":"MIT",
-    "authors":[
-        {
-            "name":"Michael Bodnarchuk"
-        }
-    ],
-    "minimum-stability": "RC",
-
-    "require": {
-        "php": ">=5.6.0 <9.0",
-        "codeception/codeception": "^4.0"
-    },
-    "autoload":{
-        "classmap": ["src/"]
-    },
-    "config": {
-        "classmap-authoritative": true
-    }
+	"name": "codeception/module-mongodb",
+	"description": "MongoDB module for Codeception",
+	"keywords": [ "codeception", "mongodb" ],
+	"homepage": "https://codeception.com/",
+	"type": "library",
+	"license": "MIT",
+	"authors": [
+		{
+			"name": "Michael Bodnarchuk"
+		}
+	],
+	"minimum-stability": "RC",
+	"require": {
+		"php": "^7.1 || ^8.0",
+		"codeception/codeception": "^4.0"
+	},
+	"autoload": {
+		"classmap": [
+			"src/"
+		]
+	},
+	"config": {
+		"classmap-authoritative": true
+	}
 }
diff --git a/readme.md b/readme.md
index 86d9967..64bb378 100644
--- a/readme.md
+++ b/readme.md
@@ -13,6 +13,10 @@ A MongoDB module for Codeception.
 composer require "codeception/module-mongodb" --dev
 ```
 
+## Requirements
+
+* `PHP 7.1` or higher.
+
 ## Documentation
 
 See [the module documentation](https://codeception.com/docs/modules/MongoDb).
diff --git a/src/Codeception/Lib/Driver/MongoDb.php b/src/Codeception/Lib/Driver/MongoDb.php
index 0880ef4..09aa46e 100644
--- a/src/Codeception/Lib/Driver/MongoDb.php
+++ b/src/Codeception/Lib/Driver/MongoDb.php
@@ -1,84 +1,62 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Codeception\Lib\Driver;
 
 use Codeception\Exception\ModuleConfigException;
 use Codeception\Exception\ModuleException;
+use Exception;
 use MongoDB\Database;
 
 class MongoDb
 {
+    /**
+     * @var int
+     */
     const DEFAULT_PORT = 27017;
-
-    private $legacy;
+    /**
+     * @var \Codeception\Lib\Driver\MongoDB|null
+     */
     private $dbh;
-    private $dsn;
+    /**
+     * @var string|null
+     */
     private $dbName;
     private $host;
     private $user;
     private $password;
+    /**
+     * @var \MongoDB\Client|null
+     */
     private $client;
+    /**
+     * @var string
+     */
     private $quiet = '';
 
-    public static function connect($dsn, $user, $password)
-    {
-        throw new \Exception(__CLASS__ . '::connect() - hm, it looked like this method had become obsolete...');
-    }
-
     /**
      * Connect to the Mongo server using the MongoDB extension.
      */
-    protected function setupMongoDB($dsn, $options)
+    protected function setupMongoDB(string $dsn, array $options): void
     {
         try {
             $this->client = new \MongoDB\Client($dsn, $options);
             $this->dbh    = $this->client->selectDatabase($this->dbName);
-        } catch (\MongoDB\Driver\Exception $e) {
-            throw new ModuleException($this, sprintf('Failed to open Mongo connection: %s', $e->getMessage()));
-        }
-    }
-
-    /**
-     * Connect to the Mongo server using the legacy mongo extension.
-     */
-    protected function setupMongo($dsn, $options)
-    {
-        try {
-            $this->client = new \MongoClient($dsn, $options);
-            $this->dbh    = $this->client->selectDB($this->dbName);
-        } catch (\MongoConnectionException $e) {
-            throw new ModuleException($this, sprintf('Failed to open Mongo connection: %s', $e->getMessage()));
+        } catch (\MongoDB\Driver\Exception $exception) {
+            throw new ModuleException($this, sprintf('Failed to open Mongo connection: %s', $exception->getMessage()));
         }
     }
 
     /**
      * Clean up the Mongo database using the MongoDB extension.
      */
-    protected function cleanupMongoDB()
+    protected function cleanupMongoDB(): void
     {
         try {
             $this->dbh->drop();
         } catch (\MongoDB\Driver\Exception $e) {
-            throw new \Exception(sprintf('Failed to drop the DB: %s', $e->getMessage()));
-        }
-    }
-
-    /**
-     * Clean up the Mongo database using the legacy Mongo extension.
-     */
-    protected function cleanupMongo()
-    {
-        try {
-            $list = $this->dbh->listCollections();
-        } catch (\MongoException $e) {
-            throw new \Exception(sprintf('Failed to list collections of the DB: %s', $e->getMessage()));
-        }
-        foreach ($list as $collection) {
-            try {
-                $collection->drop();
-            } catch (\MongoException $e) {
-                throw new \Exception(sprintf('Failed to drop collection: %s', $e->getMessage()));
-            }
+            throw new Exception(sprintf('Failed to drop the DB: %s', $e->getMessage()), $e->getCode(), $e);
         }
     }
 
@@ -87,21 +65,13 @@ protected function cleanupMongo()
      *
      * @static
      *
-     * @param $dsn
-     * @param $user
-     * @param $password
-     *
      * @throws ModuleConfigException
-     * @throws \Exception
+     * @throws Exception
      */
-    public function __construct($dsn, $user, $password)
+    public function __construct(string $dsn, string $user, string $password)
     {
-        $this->legacy = extension_loaded('mongodb') === false &&
-            class_exists('\\MongoClient') &&
-            strpos(\MongoClient::VERSION, 'mongofill') === false;
-
         /* defining DB name */
-        $this->dbName = preg_replace('/\?.*/', '', substr($dsn, strrpos($dsn, '/') + 1));
+        $this->dbName = preg_replace('#\?.*#', '', substr($dsn, strrpos($dsn, '/') + 1));
 
         if (strlen($this->dbName) == 0) {
             throw new ModuleConfigException($this, 'Please specify valid $dsn with DB name after the host:port');
@@ -109,7 +79,7 @@ class_exists('\\MongoClient') &&
 
         /* defining host */
         if (strpos($dsn, 'mongodb://') !== false) {
-            $this->host = str_replace('mongodb://', '', preg_replace('/\?.*/', '', $dsn));
+            $this->host = str_replace('mongodb://', '', preg_replace('#\?.*#', '', $dsn));
         } else {
             $this->host = $dsn;
         }
@@ -126,39 +96,31 @@ class_exists('\\MongoClient') &&
             ];
         }
 
-        $this->{$this->legacy ? 'setupMongo' : 'setupMongoDB'}($dsn, $options);
-
-        $this->dsn = $dsn;
+        $this->setupMongoDB($dsn, $options);
         $this->user = $user;
         $this->password = $password;
     }
 
     /**
      * @static
-     *
-     * @param $dsn
-     * @param $user
-     * @param $password
-     *
-     * @return MongoDb
      */
-    public static function create($dsn, $user, $password)
+    public static function create(string $dsn, string $user, string $password): \Codeception\Lib\Driver\MongoDb
     {
         return new MongoDb($dsn, $user, $password);
     }
 
-    public function cleanup()
+    public function cleanup(): void
     {
-        $this->{$this->legacy ? 'cleanupMongo' : 'cleanupMongoDB'}();
+        $this->cleanupMongoDB();
     }
 
     /**
      * dump file has to be a javascript document where one can use all the mongo shell's commands
      * just FYI: this file can be easily created be RockMongo's export button
      *
-     * @param $dumpFile
+     * @param string $dumpFile
      */
-    public function load($dumpFile)
+    public function load(string $dumpFile): void
     {
         $cmd = sprintf(
             'mongo %s %s%s',
@@ -169,9 +131,9 @@ public function load($dumpFile)
         shell_exec($cmd);
     }
 
-    public function loadFromMongoDump($dumpFile)
+    public function loadFromMongoDump(string $dumpFile): void
     {
-        list($host, $port) = $this->getHostPort();
+        [$host, $port] = $this->getHostPort();
         $cmd = sprintf(
             "mongorestore %s --host %s --port %s -d %s %s %s",
             $this->quiet,
@@ -184,9 +146,9 @@ public function loadFromMongoDump($dumpFile)
         shell_exec($cmd);
     }
 
-    public function loadFromTarGzMongoDump($dumpFile)
+    public function loadFromTarGzMongoDump(string $dumpFile): void
     {
-        list($host, $port) = $this->getHostPort();
+        [$host, $port] = $this->getHostPort();
         $getDirCmd = sprintf(
             "tar -tf %s | awk 'BEGIN { FS = \"/\" } ; { print $1 }' | uniq",
             escapeshellarg($dumpFile)
@@ -213,7 +175,7 @@ public function loadFromTarGzMongoDump($dumpFile)
         shell_exec($cmd);
     }
 
-    private function createUserPasswordCmdString()
+    private function createUserPasswordCmdString(): string
     {
         if ($this->user && $this->password) {
             return sprintf(
@@ -225,14 +187,17 @@ private function createUserPasswordCmdString()
         return '';
     }
 
+    /**
+     * @return \Codeception\Lib\Driver\MongoDb|\MongoDB\Database|null
+     */
     public function getDbh()
     {
         return $this->dbh;
     }
 
-    public function setDatabase($dbName)
+    public function setDatabase(string $dbName): void
     {
-        $this->dbh = $this->client->{$this->legacy ? 'selectDB' : 'selectDatabase'}($dbName);
+        $this->dbh = $this->client->selectDatabase($dbName);
     }
 
     public function getDbHash()
@@ -243,20 +208,13 @@ public function getDbHash()
             $result = iterator_to_array($result);
         }
 
-        return isset($result[0]->md5) ? $result[0]->md5 : null;
+        return $result[0]->md5 ?? null;
     }
 
     /**
-     * Determine if this driver is using the legacy extension or not.
-     *
-     * @return bool
+     * @return string[]|int[]
      */
-    public function isLegacy()
-    {
-        return $this->legacy;
-    }
-
-    private function getHostPort()
+    private function getHostPort(): array
     {
         $hostPort = explode(':', $this->host);
         if (count($hostPort) === 2) {
@@ -268,7 +226,7 @@ private function getHostPort()
         throw new ModuleException($this, '$dsn MUST be like (mongodb://)<host>:<port>/<db name>');
     }
 
-    public function setQuiet($quiet)
+    public function setQuiet(bool $quiet): void
     {
         $this->quiet = $quiet ? '--quiet' : '';
     }
diff --git a/src/Codeception/Module/MongoDb.php b/src/Codeception/Module/MongoDb.php
index 42a4413..5c9152c 100644
--- a/src/Codeception/Module/MongoDb.php
+++ b/src/Codeception/Module/MongoDb.php
@@ -1,13 +1,18 @@
 <?php
+
+declare(strict_types=1);
+
 namespace Codeception\Module;
 
 use Codeception\Lib\Interfaces\RequiresPackage;
-use Codeception\Module as CodeceptionModule;
+use Codeception\Module;
 use Codeception\Configuration;
 use Codeception\Exception\ModuleConfigException;
 use Codeception\Exception\ModuleException;
 use Codeception\Lib\Driver\MongoDb as MongoDbDriver;
 use Codeception\TestInterface;
+use Exception;
+use MongoConnectionException;
 
 /**
  * Works with MongoDb database.
@@ -52,10 +57,19 @@
  *   checked using the [dbHash](https://docs.mongodb.com/manual/reference/command/dbHash/) command.
  *
  */
-class MongoDb extends CodeceptionModule implements RequiresPackage
+class MongoDb extends Module implements RequiresPackage
 {
+    /**
+     * @var string
+     */
     const DUMP_TYPE_JS = 'js';
+    /**
+     * @var string
+     */
     const DUMP_TYPE_MONGODUMP = 'mongodump';
+    /**
+     * @var string
+     */
     const DUMP_TYPE_MONGODUMP_TAR_GZ = 'mongodump-tar-gz';
 
     /**
@@ -67,22 +81,32 @@ class MongoDb extends CodeceptionModule implements RequiresPackage
     /**
      * @var
      */
-
     protected $dumpFile;
+
+    /**
+     * @var bool
+     */
     protected $isDumpFileEmpty = true;
 
     protected $dbHash;
 
+    /**
+     * @var array
+     */
     protected $config = [
         'populate'  => true,
         'cleanup'   => true,
+        'dsn'       => '',
         'dump'      => null,
         'dump_type' => self::DUMP_TYPE_JS,
-        'user'      => null,
-        'password'  => null,
+        'user'      => '',
+        'password'  => '',
         'quiet'     => false,
     ];
 
+    /**
+     * @var bool
+     */
     protected $populated = false;
 
     /**
@@ -90,18 +114,20 @@ class MongoDb extends CodeceptionModule implements RequiresPackage
      */
     public $driver;
 
+    /**
+     * @var string[]
+     */
     protected $requiredFields = ['dsn'];
 
     public function _initialize()
     {
-
         try {
             $this->driver = MongoDbDriver::create(
                 $this->config['dsn'],
                 $this->config['user'],
                 $this->config['password']
             );
-        } catch (\MongoConnectionException $e) {
+        } catch (MongoConnectionException $e) {
             throw new ModuleException(__CLASS__, $e->getMessage() . ' while creating Mongo connection');
         }
 
@@ -113,9 +139,9 @@ public function _initialize()
         }
     }
 
-    private function validateDump()
+    private function validateDump(): void
     {
-        if ($this->config['dump'] && ($this->config['cleanup'] or ($this->config['populate']))) {
+        if ($this->config['dump'] && ($this->config['cleanup'] || $this->config['populate'])) {
             if (!file_exists(Configuration::projectDir() . $this->config['dump'])) {
                 throw new ModuleConfigException(
                     __CLASS__,
@@ -128,8 +154,8 @@ private function validateDump()
 
             if ($this->config['dump_type'] === self::DUMP_TYPE_JS) {
                 $content = file_get_contents($this->dumpFile);
-                $content = trim(preg_replace('%/\*(?:(?!\*/).)*\*/%s', "", $content));
-                if (!sizeof(explode("\n", $content))) {
+                $content = trim(preg_replace('#/\*(?:(?!\*/).)*\*/#s', "", $content));
+                if (count(explode("\n", $content)) === 0) {
                     $this->isDumpFileEmpty = true;
                 }
                 return;
@@ -162,7 +188,7 @@ private function validateDump()
                         "Tar gunzip archives are not supported for Windows systems"
                     );
                 }
-                if (!preg_match('/(\.tar\.gz|\.tgz)$/', $this->dumpFile)) {
+                if (!preg_match('#(\.tar\.gz|\.tgz)$#', $this->dumpFile)) {
                     throw new ModuleConfigException(
                         __CLASS__,
                         "Dump file must be a valid tar gunzip archive.\n
@@ -195,7 +221,7 @@ public function _after(TestInterface $test)
         $this->populated = false;
     }
 
-    protected function shouldCleanup()
+    protected function shouldCleanup(): bool
     {
         if ($this->populated) {
             return false;
@@ -206,7 +232,7 @@ protected function shouldCleanup()
             : (bool)$this->config['cleanup'];
     }
 
-    protected function cleanup()
+    protected function cleanup(): void
     {
         $dbh = $this->driver->getDbh();
         if (!$dbh) {
@@ -217,12 +243,12 @@ protected function cleanup()
         }
         try {
             $this->driver->cleanup();
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             throw new ModuleException(__CLASS__, $e->getMessage());
         }
     }
 
-    protected function loadDump()
+    protected function loadDump(): void
     {
         $this->validateDump();
 
@@ -242,7 +268,7 @@ protected function loadDump()
                 $this->driver->setQuiet($this->config['quiet']);
                 $this->driver->loadFromTarGzMongoDump($this->dumpFile);
             }
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             throw new ModuleException(__CLASS__, $e->getMessage());
         }
 
@@ -254,14 +280,14 @@ protected function loadDump()
     /**
      * Specify the database to use
      *
-     * ``` php
+     * ```php
      * <?php
      * $I->useDatabase('db_1');
      * ```
      *
-     * @param $dbName
+     * @param string $dbName
      */
-    public function useDatabase($dbName)
+    public function useDatabase(string $dbName): void
     {
         $this->driver->setDatabase($dbName);
     }
@@ -269,22 +295,19 @@ public function useDatabase($dbName)
     /**
      * Inserts data into collection
      *
-     * ``` php
+     * ```php
      * <?php
-     * $I->haveInCollection('users', array('name' => 'John', 'email' => 'john@coltrane.com'));
-     * $user_id = $I->haveInCollection('users', array('email' => 'john@coltrane.com'));
+     * $I->haveInCollection('users', ['name' => 'John', 'email' => 'john@coltrane.com']);
+     * $user_id = $I->haveInCollection('users', ['email' => 'john@coltrane.com']);
      * ```
      *
-     * @param $collection
+     * @param string $collection
      * @param array $data
+     * @return string
      */
-    public function haveInCollection($collection, array $data)
+    public function haveInCollection(string $collection, array $data): string
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
-        if ($this->driver->isLegacy()) {
-            $collection->insert($data);
-            return $data['_id'];
-        }
 
         $response = $collection->insertOne($data);
         return (string) $response->getInsertedId();
@@ -293,15 +316,14 @@ public function haveInCollection($collection, array $data)
     /**
      * Checks if collection contains an item.
      *
-     * ``` php
+     * ```php
      * <?php
-     * $I->seeInCollection('users', array('name' => 'miles'));
+     * $I->seeInCollection('users', ['name' => 'miles']);
      * ```
      *
-     * @param $collection
-     * @param array $criteria
+     * @param string $collection
      */
-    public function seeInCollection($collection, $criteria = [])
+    public function seeInCollection(string $collection, array $criteria = []): void
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
         $res = $collection->count($criteria);
@@ -311,15 +333,14 @@ public function seeInCollection($collection, $criteria = [])
     /**
      * Checks if collection doesn't contain an item.
      *
-     * ``` php
+     * ```php
      * <?php
-     * $I->dontSeeInCollection('users', array('name' => 'miles'));
+     * $I->dontSeeInCollection('users', ['name' => 'miles']);
      * ```
      *
-     * @param $collection
-     * @param array $criteria
+     * @param string $collection
      */
-    public function dontSeeInCollection($collection, $criteria = [])
+    public function dontSeeInCollection(string $collection, array $criteria = []): void
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
         $res = $collection->count($criteria);
@@ -329,16 +350,15 @@ public function dontSeeInCollection($collection, $criteria = [])
     /**
      * Grabs a data from collection
      *
-     * ``` php
+     * ```php
      * <?php
-     * $user = $I->grabFromCollection('users', array('name' => 'miles'));
+     * $user = $I->grabFromCollection('users', ['name' => 'miles']);
      * ```
      *
-     * @param $collection
-     * @param array $criteria
-     * @return array
+     * @param string $collection
+     * @return \MongoDB\Model\BSONDocument|mixed
      */
-    public function grabFromCollection($collection, $criteria = [])
+    public function grabFromCollection(string $collection, array $criteria = [])
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
         return $collection->findOne($criteria);
@@ -347,18 +367,16 @@ public function grabFromCollection($collection, $criteria = [])
     /**
      * Grabs the documents count from a collection
      *
-     * ``` php
+     * ```php
      * <?php
      * $count = $I->grabCollectionCount('users');
      * // or
-     * $count = $I->grabCollectionCount('users', array('isAdmin' => true));
+     * $count = $I->grabCollectionCount('users', ['isAdmin' => true]);
      * ```
      *
-     * @param $collection
-     * @param array $criteria
-     * @return integer
+     * @param string $collection
      */
-    public function grabCollectionCount($collection, $criteria = [])
+    public function grabCollectionCount(string $collection, array $criteria = []): int
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
         return $collection->count($criteria);
@@ -367,16 +385,12 @@ public function grabCollectionCount($collection, $criteria = [])
     /**
      * Asserts that an element in a collection exists and is an Array
      *
-     * ``` php
+     * ```php
      * <?php
-     * $I->seeElementIsArray('users', array('name' => 'John Doe') , 'data.skills');
+     * $I->seeElementIsArray('users', ['name' => 'John Doe'], 'data.skills');
      * ```
-     *
-     * @param String $collection
-     * @param Array $criteria
-     * @param String $elementToCheck
      */
-    public function seeElementIsArray($collection, $criteria = [], $elementToCheck = null)
+    public function seeElementIsArray(string $collection, array $criteria = [], string $elementToCheck = null): void
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
 
@@ -385,7 +399,7 @@ public function seeElementIsArray($collection, $criteria = [], $elementToCheck =
                 $criteria,
                 [
                     $elementToCheck => ['$exists' => true],
-                    '$where' => "Array.isArray(this.{$elementToCheck})"
+                    '$where' => sprintf('Array.isArray(this.%s)', $elementToCheck)
                 ]
             )
         );
@@ -400,16 +414,12 @@ public function seeElementIsArray($collection, $criteria = [], $elementToCheck =
     /**
      * Asserts that an element in a collection exists and is an Object
      *
-     * ``` php
+     * ```php
      * <?php
-     * $I->seeElementIsObject('users', array('name' => 'John Doe') , 'data');
+     * $I->seeElementIsObject('users', ['name' => 'John Doe'], 'data');
      * ```
-     *
-     * @param String $collection
-     * @param Array $criteria
-     * @param String $elementToCheck
      */
-    public function seeElementIsObject($collection, $criteria = [], $elementToCheck = null)
+    public function seeElementIsObject(string $collection, array $criteria = [], string $elementToCheck = null): void
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
 
@@ -418,7 +428,7 @@ public function seeElementIsObject($collection, $criteria = [], $elementToCheck
                 $criteria,
                 [
                     $elementToCheck => ['$exists' => true],
-                    '$where' => "! Array.isArray(this.{$elementToCheck}) && isObject(this.{$elementToCheck})"
+                    '$where' => sprintf('! Array.isArray(this.%s) && isObject(this.%s)', $elementToCheck, $elementToCheck)
                 ]
             )
         );
@@ -433,17 +443,15 @@ public function seeElementIsObject($collection, $criteria = [], $elementToCheck
     /**
      * Count number of records in a collection
      *
-     * ``` php
+     * ```php
      * <?php
      * $I->seeNumElementsInCollection('users', 2);
-     * $I->seeNumElementsInCollection('users', 1, array('name' => 'miles'));
+     * $I->seeNumElementsInCollection('users', 1, ['name' => 'miles']);
      * ```
      *
-     * @param $collection
-     * @param integer $expected
-     * @param array $criteria
+     * @param string $collection
      */
-    public function seeNumElementsInCollection($collection, $expected, $criteria = [])
+    public function seeNumElementsInCollection(string $collection, int $expected, array $criteria = []): void
     {
         $collection = $this->driver->getDbh()->selectCollection($collection);
         $res = $collection->count($criteria);
@@ -452,6 +460,8 @@ public function seeNumElementsInCollection($collection, $expected, $criteria = [
 
     /**
      * Returns list of classes and corresponding packages required for this module
+     *
+     * @return array<string, string>
      */
     public function _requires()
     {
diff --git a/tests/unit/Codeception/Module/MongoDbLegacyTest.php b/tests/unit/Codeception/Module/MongoDbLegacyTest.php
deleted file mode 100644
index 4c8e9d8..0000000
--- a/tests/unit/Codeception/Module/MongoDbLegacyTest.php
+++ /dev/null
@@ -1,149 +0,0 @@
-<?php
-
-use Codeception\Module\MongoDb;
-
-class MongoDbLegacyTest extends \Codeception\PHPUnit\TestCase
-{
-    /**
-     * @var array
-     */
-    private $mongoConfig = array(
-        'dsn' => 'mongodb://localhost:27017/test'
-    );
-
-    /**
-     * @var MongoDb
-     */
-    protected $module;
-
-    /**
-     * @var \MongoDb
-     */
-    protected $db;
-
-    /**
-     * @var \MongoCollection
-     */
-    private $userCollection;
-
-    protected function _setUp()
-    {
-        if (!class_exists('Mongo')) {
-            $this->markTestSkipped('Mongo is not installed');
-        }
-        if (!class_exists('MongoDB\Client')) {
-            $this->markTestSkipped('MongoDb\Client is not installed');
-        }
-
-        $mongo = new \MongoClient();
-
-        $container = \Codeception\Util\Stub::make('Codeception\Lib\ModuleContainer');
-        $this->module = new MongoDb($container);
-        $this->module->_setConfig($this->mongoConfig);
-        $this->module->_initialize();
-
-        $this->db = $mongo->selectDB('test');
-        $this->userCollection = $this->db->createCollection('users');
-        $this->userCollection->insert(array('id' => 1, 'email' => 'miles@davis.com'));
-    }
-
-    protected function _tearDown()
-    {
-        if (!is_null($this->userCollection)) {
-            $this->userCollection->drop();
-        }
-    }
-
-    public function testSeeInCollection()
-    {
-        $this->module->seeInCollection('users', array('email' => 'miles@davis.com'));
-    }
-
-    public function testDontSeeInCollection()
-    {
-        $this->module->dontSeeInCollection('users', array('email' => 'davert@davert.com'));
-    }
-
-    public function testHaveAndSeeInCollection()
-    {
-        $this->module->haveInCollection('users', array('name' => 'John', 'email' => 'john@coltrane.com'));
-        $this->module->seeInCollection('users', array('name' => 'John', 'email' => 'john@coltrane.com'));
-    }
-
-    public function testGrabFromCollection()
-    {
-        $user = $this->module->grabFromCollection('users', array('id' => 1));
-        $this->assertArrayHasKey('email', $user);
-        $this->assertEquals('miles@davis.com', $user['email']);
-    }
-
-    public function testSeeNumElementsInCollection()
-    {
-        $this->module->seeNumElementsInCollection('users', 1);
-        $this->module->seeNumElementsInCollection('users', 1, array('email' => 'miles@davis.com'));
-        $this->module->seeNumElementsInCollection('users', 0, array('name' => 'Doe'));
-    }
-
-    public function testGrabCollectionCount()
-    {
-        $this->userCollection->insert(array('id' => 2, 'email' => 'louis@armstrong.com'));
-        $this->userCollection->insert(array('id' => 3, 'email' => 'dizzy@gillespie.com'));
-
-        $this->assertEquals(1, $this->module->grabCollectionCount('users', array('id' => 3)));
-        $this->assertEquals(3, $this->module->grabCollectionCount('users'));
-    }
-
-    public function testSeeElementIsArray()
-    {
-        $this->userCollection->insert(array('id' => 4, 'trumpets' => array('piccolo', 'bass', 'slide')));
-
-        $this->module->seeElementIsArray('users', array('id' => 4), 'trumpets');
-    }
-
-
-    public function testSeeElementIsArrayThrowsError()
-    {
-        $this->expectException('PHPUnit\Framework\ExpectationFailedException');
-
-        $this->userCollection->insert(array('id' => 5, 'trumpets' => array('piccolo', 'bass', 'slide')));
-        $this->userCollection->insert(array('id' => 6, 'trumpets' => array('piccolo', 'bass', 'slide')));
-        $this->module->seeElementIsArray('users', array(), 'trumpets');
-    }
-
-    public function testSeeElementIsObject()
-    {
-        $trumpet = new \StdClass;
-
-        $trumpet->name = 'Trumpet 1';
-        $trumpet->pitch = 'B♭';
-        $trumpet->price = array('min' => 458, 'max' => 891);
-
-        $this->userCollection->insert(array('id' => 6, 'trumpet' => $trumpet));
-
-        $this->module->seeElementIsObject('users', array('id' => 6), 'trumpet');
-    }
-
-    public function testSeeElementIsObjectThrowsError()
-    {
-        $trumpet = new \StdClass;
-
-        $trumpet->name = 'Trumpet 1';
-        $trumpet->pitch = 'B♭';
-        $trumpet->price = array('min' => 458, 'max' => 891);
-
-        $this->expectException('PHPUnit\Framework\ExpectationFailedException');
-
-        $this->userCollection->insert(array('id' => 5, 'trumpet' => $trumpet));
-        $this->userCollection->insert(array('id' => 6, 'trumpet' => $trumpet));
-
-        $this->module->seeElementIsObject('users', array(), 'trumpet');
-    }
-
-    public function testUseDatabase()
-    {
-        $this->module->useDatabase('example');
-        $this->module->haveInCollection('stuff', array('name' => 'Ashley', 'email' => 'me@ashleyclarke.me'));
-        $this->module->seeInCollection('stuff', array('name' => 'Ashley', 'email' => 'me@ashleyclarke.me'));
-        $this->module->dontSeeInCollection('users', array('email' => 'miles@davis.com'));
-    }
-}
diff --git a/tests/unit/Codeception/Module/MongoDbTest.php b/tests/unit/Codeception/Module/MongoDbTest.php
index cc053d2..9ea3990 100644
--- a/tests/unit/Codeception/Module/MongoDbTest.php
+++ b/tests/unit/Codeception/Module/MongoDbTest.php
@@ -1,19 +1,24 @@
 <?php
 
+declare(strict_types=1);
+
+use Codeception\Lib\ModuleContainer;
 use Codeception\Module\MongoDb;
 use Codeception\Exception\ModuleException;
 use Codeception\Test\Unit;
+use Codeception\Util\Stub;
+use PHPUnit\Framework\ExpectationFailedException;
 
-class MongoDbTest extends Unit
+final class MongoDbTest extends Unit
 {
     /**
      * @var array
      */
-    private $mongoConfig = array(
+    private $mongoConfig = [
         'dsn' => 'mongodb://localhost:27017/test?connectTimeoutMS=300',
         'dump' => 'tests/data/dumps/mongo.js',
         'populate' => true
-    );
+    ];
 
     /**
      * @var MongoDb
@@ -39,22 +44,22 @@ protected function _setUp()
         $cleanupDirty = in_array('cleanup-dirty', $this->getGroups());
         $config = $this->mongoConfig + ['cleanup' => $cleanupDirty ? 'dirty' : true];
 
-        $mongo = new \MongoDB\Client();
+        $client = new \MongoDB\Client();
 
-        $container = \Codeception\Util\Stub::make('Codeception\Lib\ModuleContainer');
+        $container = Stub::make(ModuleContainer::class);
         $this->module = new MongoDb($container);
         $this->module->_setConfig($config);
         try {
             $this->module->_initialize();
-        } catch (ModuleException $e) {
-            $this->markTestSkipped($e->getMessage());
+        } catch (ModuleException $moduleException) {
+            $this->markTestSkipped($moduleException->getMessage());
         }
 
-        $this->db = $mongo->selectDatabase('test');
+        $this->db = $client->selectDatabase('test');
         $this->userCollection = $this->db->users;
 
         if (!$cleanupDirty) {
-            $this->userCollection->insertOne(array('id' => 1, 'email' => 'miles@davis.com'));
+            $this->userCollection->insertOne(['id' => 1, 'email' => 'miles@davis.com']);
         }
     }
 
@@ -67,23 +72,23 @@ protected function _tearDown()
 
     public function testSeeInCollection()
     {
-        $this->module->seeInCollection('users', array('email' => 'miles@davis.com'));
+        $this->module->seeInCollection('users', ['email' => 'miles@davis.com']);
     }
 
     public function testDontSeeInCollection()
     {
-        $this->module->dontSeeInCollection('users', array('email' => 'davert@davert.com'));
+        $this->module->dontSeeInCollection('users', ['email' => 'davert@davert.com']);
     }
 
     public function testHaveAndSeeInCollection()
     {
-        $this->module->haveInCollection('users', array('name' => 'John', 'email' => 'john@coltrane.com'));
-        $this->module->seeInCollection('users', array('name' => 'John', 'email' => 'john@coltrane.com'));
+        $this->module->haveInCollection('users', ['name' => 'John', 'email' => 'john@coltrane.com']);
+        $this->module->seeInCollection('users', ['name' => 'John', 'email' => 'john@coltrane.com']);
     }
 
     public function testGrabFromCollection()
     {
-        $user = $this->module->grabFromCollection('users', array('id' => 1));
+        $user = $this->module->grabFromCollection('users', ['id' => 1]);
         $this->assertArrayHasKey('email', $user);
         $this->assertEquals('miles@davis.com', $user['email']);
     }
@@ -91,71 +96,72 @@ public function testGrabFromCollection()
     public function testSeeNumElementsInCollection()
     {
         $this->module->seeNumElementsInCollection('users', 1);
-        $this->module->seeNumElementsInCollection('users', 1, array('email' => 'miles@davis.com'));
-        $this->module->seeNumElementsInCollection('users', 0, array('name' => 'Doe'));
+        $this->module->seeNumElementsInCollection('users', 1, ['email' => 'miles@davis.com']);
+        $this->module->seeNumElementsInCollection('users', 0, ['name' => 'Doe']);
     }
 
     public function testGrabCollectionCount()
     {
-        $this->userCollection->insertOne(array('id' => 2, 'email' => 'louis@armstrong.com'));
-        $this->userCollection->insertOne(array('id' => 3, 'email' => 'dizzy@gillespie.com'));
+        $this->userCollection->insertOne(['id' => 2, 'email' => 'louis@armstrong.com']);
+        $this->userCollection->insertOne(['id' => 3, 'email' => 'dizzy@gillespie.com']);
 
-        $this->assertEquals(1, $this->module->grabCollectionCount('users', array('id' => 3)));
+        $this->assertEquals(1, $this->module->grabCollectionCount('users', ['id' => 3]));
         $this->assertEquals(3, $this->module->grabCollectionCount('users'));
     }
 
     public function testSeeElementIsArray()
     {
-        $this->userCollection->insertOne(array('id' => 4, 'trumpets' => array('piccolo', 'bass', 'slide')));
+        $this->userCollection->insertOne(['id' => 4, 'trumpets' => ['piccolo', 'bass', 'slide']]);
 
-        $this->module->seeElementIsArray('users', array('id' => 4), 'trumpets');
+        $this->module->seeElementIsArray('users', ['id' => 4], 'trumpets');
     }
 
 
     public function testSeeElementIsArrayThrowsError()
     {
-        $this->expectException('PHPUnit\Framework\ExpectationFailedException');
+        $this->expectException(ExpectationFailedException::class);
 
-        $this->userCollection->insertOne(array('id' => 5, 'trumpets' => array('piccolo', 'bass', 'slide')));
-        $this->userCollection->insertOne(array('id' => 6, 'trumpets' => array('piccolo', 'bass', 'slide')));
-        $this->module->seeElementIsArray('users', array(), 'trumpets');
+        $this->userCollection->insertOne(['id' => 5, 'trumpets' => ['piccolo', 'bass', 'slide']]);
+        $this->userCollection->insertOne(['id' => 6, 'trumpets' => ['piccolo', 'bass', 'slide']]);
+        
+        $this->module->seeElementIsArray('users', [], 'trumpets');
     }
 
     public function testSeeElementIsObject()
     {
-        $trumpet = new \StdClass;
+        $trumpet = new StdClass;
 
         $trumpet->name = 'Trumpet 1';
         $trumpet->pitch = 'B♭';
-        $trumpet->price = array('min' => 458, 'max' => 891);
+        $trumpet->price = ['min' => 458, 'max' => 891];
 
-        $this->userCollection->insertOne(array('id' => 6, 'trumpet' => $trumpet));
+        $this->userCollection->insertOne(['id' => 6, 'trumpet' => $trumpet]);
 
-        $this->module->seeElementIsObject('users', array('id' => 6), 'trumpet');
+        $this->module->seeElementIsObject('users', ['id' => 6], 'trumpet');
     }
 
     public function testSeeElementIsObjectThrowsError()
     {
-        $trumpet = new \StdClass;
+        $trumpet = new StdClass;
 
         $trumpet->name = 'Trumpet 1';
         $trumpet->pitch = 'B♭';
-        $trumpet->price = array('min' => 458, 'max' => 891);
+        $trumpet->price = ['min' => 458, 'max' => 891];
 
-        $this->expectException('PHPUnit\Framework\ExpectationFailedException');
+        $this->expectException(ExpectationFailedException::class);
 
-        $this->userCollection->insertOne(array('id' => 5, 'trumpet' => $trumpet));
-        $this->userCollection->insertOne(array('id' => 6, 'trumpet' => $trumpet));
+        $this->userCollection->insertOne(['id' => 5, 'trumpet' => $trumpet]);
+        $this->userCollection->insertOne(['id' => 6, 'trumpet' => $trumpet]);
 
-        $this->module->seeElementIsObject('users', array(), 'trumpet');
+        $this->module->seeElementIsObject('users', [], 'trumpet');
     }
 
     public function testUseDatabase()
     {
         $this->module->useDatabase('example');
-        $this->module->haveInCollection('stuff', array('name' => 'Ashley', 'email' => 'me@ashleyclarke.me'));
-        $this->module->seeInCollection('stuff', array('name' => 'Ashley', 'email' => 'me@ashleyclarke.me'));
-        $this->module->dontSeeInCollection('users', array('email' => 'miles@davis.com'));
+        $this->module->haveInCollection('stuff', ['name' => 'Ashley', 'email' => 'me@ashleyclarke.me']);
+        $this->module->seeInCollection('stuff', ['name' => 'Ashley', 'email' => 'me@ashleyclarke.me']);
+        $this->module->dontSeeInCollection('users', ['email' => 'miles@davis.com']);
     }
 
     public function testLoadDump()
@@ -180,7 +186,7 @@ public function testLoadDump()
      */
     public function testCleanupDirty()
     {
-        $test = $this->createMock('Codeception\TestInterface');
+        $test = $this->createMock(\Codeception\TestInterface::class);
         $collection = $this->db->selectCollection('96_bulls');
 
         $hash1 = $this->module->driver->getDbHash();
@@ -192,7 +198,7 @@ public function testCleanupDirty()
         $this->module->_before($test); // No cleanup expected
 
         $this->assertEquals($hash1, $this->module->driver->getDbHash());
-        $collection->insertOne(array('name' => 'Coby White','position' => 'pg'));
+        $collection->insertOne(['name' => 'Coby White','position' => 'pg']);
 
         $hashDirty = $this->module->driver->getDbHash();
         $this->assertNotEquals($hash1, $hashDirty);