diff --git a/composer.json b/composer.json
index 3b8d229d..96e6e428 100755
--- a/composer.json
+++ b/composer.json
@@ -89,7 +89,8 @@
     "padraic/phar-updater": "^1.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^5.7"
+    "phpunit/phpunit": "^5.7",
+    "mockery/mockery": "^1.3"
   },
   "config": {
     "platform": {
diff --git a/composer.lock b/composer.lock
index 8bed47e1..7a71153e 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "7ec8559bdf0136a99e1f68c2c278d24e",
+    "content-hash": "ee277424273531d2fad2697a3476b87c",
     "packages": [
         {
             "name": "composer/ca-bundle",
@@ -1843,6 +1843,118 @@
             ],
             "time": "2015-06-14T21:17:01+00:00"
         },
+        {
+            "name": "hamcrest/hamcrest-php",
+            "version": "v2.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/hamcrest/hamcrest-php.git",
+                "reference": "8c3d0a3f6af734494ad8f6fbbee0ba92422859f3"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/hamcrest/hamcrest-php/zipball/8c3d0a3f6af734494ad8f6fbbee0ba92422859f3",
+                "reference": "8c3d0a3f6af734494ad8f6fbbee0ba92422859f3",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3|^7.0|^8.0"
+            },
+            "replace": {
+                "cordoval/hamcrest-php": "*",
+                "davedevelopment/hamcrest-php": "*",
+                "kodova/hamcrest-php": "*"
+            },
+            "require-dev": {
+                "phpunit/php-file-iterator": "^1.4 || ^2.0",
+                "phpunit/phpunit": "^4.8.36 || ^5.7 || ^6.5 || ^7.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.1-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "hamcrest"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "description": "This is the PHP port of Hamcrest Matchers",
+            "keywords": [
+                "test"
+            ],
+            "time": "2020-07-09T08:09:16+00:00"
+        },
+        {
+            "name": "mockery/mockery",
+            "version": "1.3.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/mockery/mockery.git",
+                "reference": "60fa2f67f6e4d3634bb4a45ff3171fa52215800d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/mockery/mockery/zipball/60fa2f67f6e4d3634bb4a45ff3171fa52215800d",
+                "reference": "60fa2f67f6e4d3634bb4a45ff3171fa52215800d",
+                "shasum": ""
+            },
+            "require": {
+                "hamcrest/hamcrest-php": "^2.0.1",
+                "lib-pcre": ">=7.0",
+                "php": ">=5.6.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^5.7.10|^6.5|^7.5|^8.5|^9.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "Mockery": "library/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Pádraic Brady",
+                    "email": "padraic.brady@gmail.com",
+                    "homepage": "http://blog.astrumfutura.com"
+                },
+                {
+                    "name": "Dave Marshall",
+                    "email": "dave.marshall@atstsolutions.co.uk",
+                    "homepage": "http://davedevelopment.co.uk"
+                }
+            ],
+            "description": "Mockery is a simple yet flexible PHP mock object framework",
+            "homepage": "https://github.com/mockery/mockery",
+            "keywords": [
+                "BDD",
+                "TDD",
+                "library",
+                "mock",
+                "mock objects",
+                "mockery",
+                "stub",
+                "test",
+                "test double",
+                "testing"
+            ],
+            "time": "2020-08-11T18:10:21+00:00"
+        },
         {
             "name": "myclabs/deep-copy",
             "version": "1.7.0",
diff --git a/tests/Fake/Process/DummyExecute.php b/tests/Fake/Process/DummyExecute.php
index 4c729a94..4d06cc06 100644
--- a/tests/Fake/Process/DummyExecute.php
+++ b/tests/Fake/Process/DummyExecute.php
@@ -17,15 +17,36 @@
 
 class DummyExecute extends Execute
 {
+    private function getMockProcess($cmd)
+    {
+        $process = \Mockery::mock('Symfony\Component\Process\Process');
+        $process->shouldReceive(
+            'setTimeout',
+            'run',
+            'wait',
+            'stop',
+            'getExitCode',
+            'getExitCodeText',
+            'getWorkingDirectory',
+            'isOutputDisabled',
+            'getErrorOutput'
+        );
+
+        $process->shouldReceive('isSuccessful')->andReturn(true);
+        $process->shouldReceive('getOutput')->andReturn('');
+        $process->shouldReceive('getCommandLine')->andReturn($cmd);
+
+        return $process;
+    }
+
     public function run($cmd, $error = null)
     {
         if ($cmd instanceof Process) {
             // Get the command line from process.
             $cmd = $cmd->getCommandLine();
         }
-        $cmd = new DummyProcess($cmd);
 
-        return $this->helper->run($this->output, $cmd, $error);
+        return $this->helper->run($this->output, $this->getMockProcess($cmd), $error);
     }
 
     public function mustRun($cmd, $error = null)
@@ -34,9 +55,8 @@ public function mustRun($cmd, $error = null)
             // Get the command line from process.
             $cmd = $cmd->getCommandLine();
         }
-        $cmd = new DummyProcess($cmd);
 
-        return $this->helper->mustRun($this->output, $cmd, $error);
+        return $this->helper->mustRun($this->output, $this->getMockProcess($cmd), $error);
     }
 
     public function runAll($processes)
@@ -51,15 +71,15 @@ public function mustRunAll($processes)
 
     public function passThrough($commandline, $cwd = null, $timeout = null)
     {
-        return $this->passThroughProcess(new DummyProcess($commandline, $cwd, null, null, $timeout));
+        return $this->passThroughProcess($this->getMockProcess($commandline));
     }
 
     public function passThroughProcess(Process $process)
     {
-        if ($process instanceof DummyProcess) {
+        if ($process instanceof \Mockery\MockInterface) {
             return $process;
         }
 
-        return new DummyProcess($process->getCommandLine(), $process->getWorkingDirectory(), null, null, $process->getTimeout());
+        return $this->getMockProcess($process->getCommandLine());
     }
 }
diff --git a/tests/Fake/Process/DummyProcess.php b/tests/Fake/Process/DummyProcess.php
deleted file mode 100644
index d412a39f..00000000
--- a/tests/Fake/Process/DummyProcess.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-/*
- * This file is part of the Moodle Plugin CI package.
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- *
- * Copyright (c) 2018 Blackboard Inc. (http://www.blackboard.com)
- * License http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-namespace MoodlePluginCI\Tests\Fake\Process;
-
-use Symfony\Component\Process\Process;
-
-class DummyProcess extends Process
-{
-    private $realcommandline;
-
-    public function __construct($commandline)
-    {
-        $this->realcommandline = $commandline;
-    }
-
-    public function getCommandLine()
-    {
-        return $this->realcommandline;
-    }
-
-    public function getOutput()
-    {
-        return '';
-    }
-
-    public function isSuccessful()
-    {
-        return true;
-    }
-}