diff --git a/.tmux b/.tmux
index 1b6539c..9e021e4 100755
--- a/.tmux
+++ b/.tmux
@@ -20,7 +20,7 @@ tmux send-keys -t "${session_name}:vim" "nvim" Enter
 tmux split-pane -t "${session_name}:vim" -h -c "${session_path}" -p 40
 tmux send-keys -t "${session_name}:vim.right" "php -S 0.0.0.0:9000 -t web" Enter
 tmux split-pane -t "${session_name}:vim" -c "${session_path}" -v
-tmux send-keys -t "${session_name}:vim.bottom-right" "watch-changes web/modules/custom phpunit" Enter
+tmux send-keys -t "${session_name}:vim.bottom-right" "paratest && watch-changes web/modules/custom paratest" Enter
 
 # 2. General shell use.
 tmux new-window -t "${session_name}" -c "${session_path}"
diff --git a/composer.json b/composer.json
index 5108ba8..7dd1508 100644
--- a/composer.json
+++ b/composer.json
@@ -94,6 +94,7 @@
         }
     },
     "require-dev": {
+        "brianium/paratest": "^6.11",
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
         "drupal/coder": "^8.3",
         "drupal/core-dev": "^10.2"
diff --git a/composer.lock b/composer.lock
index a2859e1..b6b9638 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": "821af42d7f19e2fd7b4c9d3cfeaedc42",
+    "content-hash": "5343c09aed0b03db697c232f5f43ec61",
     "packages": [
         {
             "name": "asm89/stack-cors",
@@ -4902,6 +4902,98 @@
             },
             "time": "2023-12-09T11:58:45+00:00"
         },
+        {
+            "name": "brianium/paratest",
+            "version": "v6.11.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/paratestphp/paratest.git",
+                "reference": "8083a421cee7dad847ee7c464529043ba30de380"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/paratestphp/paratest/zipball/8083a421cee7dad847ee7c464529043ba30de380",
+                "reference": "8083a421cee7dad847ee7c464529043ba30de380",
+                "shasum": ""
+            },
+            "require": {
+                "ext-dom": "*",
+                "ext-pcre": "*",
+                "ext-reflection": "*",
+                "ext-simplexml": "*",
+                "fidry/cpu-core-counter": "^0.4.1 || ^0.5.1 || ^1.0.0",
+                "jean85/pretty-package-versions": "^2.0.5",
+                "php": "^7.3 || ^8.0",
+                "phpunit/php-code-coverage": "^9.2.25",
+                "phpunit/php-file-iterator": "^3.0.6",
+                "phpunit/php-timer": "^5.0.3",
+                "phpunit/phpunit": "^9.6.4",
+                "sebastian/environment": "^5.1.5",
+                "symfony/console": "^5.4.28 || ^6.3.4 || ^7.0.0",
+                "symfony/process": "^5.4.28 || ^6.3.4 || ^7.0.0"
+            },
+            "require-dev": {
+                "doctrine/coding-standard": "^12.0.0",
+                "ext-pcov": "*",
+                "ext-posix": "*",
+                "infection/infection": "^0.27.6",
+                "squizlabs/php_codesniffer": "^3.7.2",
+                "symfony/filesystem": "^5.4.25 || ^6.3.1 || ^7.0.0",
+                "vimeo/psalm": "^5.7.7"
+            },
+            "bin": [
+                "bin/paratest",
+                "bin/paratest.bat",
+                "bin/paratest_for_phpstorm"
+            ],
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "ParaTest\\": [
+                        "src/"
+                    ]
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Brian Scaturro",
+                    "email": "scaturrob@gmail.com",
+                    "role": "Developer"
+                },
+                {
+                    "name": "Filippo Tessarotto",
+                    "email": "zoeslam@gmail.com",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Parallel testing for PHP",
+            "homepage": "https://github.com/paratestphp/paratest",
+            "keywords": [
+                "concurrent",
+                "parallel",
+                "phpunit",
+                "testing"
+            ],
+            "support": {
+                "issues": "https://github.com/paratestphp/paratest/issues",
+                "source": "https://github.com/paratestphp/paratest/tree/v6.11.0"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/sponsors/Slamdunk",
+                    "type": "github"
+                },
+                {
+                    "url": "https://paypal.me/filippotessarotto",
+                    "type": "paypal"
+                }
+            ],
+            "time": "2023-10-31T09:13:57+00:00"
+        },
         {
             "name": "colinodell/psr-testlogger",
             "version": "v1.3.0",
@@ -5785,6 +5877,67 @@
             },
             "time": "2023-12-12T22:01:45+00:00"
         },
+        {
+            "name": "fidry/cpu-core-counter",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/theofidry/cpu-core-counter.git",
+                "reference": "85193c0b0cb5c47894b5eaec906e946f054e7077"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/theofidry/cpu-core-counter/zipball/85193c0b0cb5c47894b5eaec906e946f054e7077",
+                "reference": "85193c0b0cb5c47894b5eaec906e946f054e7077",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2 || ^8.0"
+            },
+            "require-dev": {
+                "fidry/makefile": "^0.2.0",
+                "fidry/php-cs-fixer-config": "^1.1.2",
+                "phpstan/extension-installer": "^1.2.0",
+                "phpstan/phpstan": "^1.9.2",
+                "phpstan/phpstan-deprecation-rules": "^1.0.0",
+                "phpstan/phpstan-phpunit": "^1.2.2",
+                "phpstan/phpstan-strict-rules": "^1.4.4",
+                "phpunit/phpunit": "^8.5.31 || ^9.5.26",
+                "webmozarts/strict-phpunit": "^7.5"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Fidry\\CpuCoreCounter\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Théo FIDRY",
+                    "email": "theo.fidry@gmail.com"
+                }
+            ],
+            "description": "Tiny utility to get the number of CPU cores.",
+            "keywords": [
+                "CPU",
+                "core"
+            ],
+            "support": {
+                "issues": "https://github.com/theofidry/cpu-core-counter/issues",
+                "source": "https://github.com/theofidry/cpu-core-counter/tree/1.0.0"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/theofidry",
+                    "type": "github"
+                }
+            ],
+            "time": "2023-09-17T21:38:23+00:00"
+        },
         {
             "name": "google/protobuf",
             "version": "v3.25.1",
@@ -5892,6 +6045,65 @@
             },
             "time": "2023-12-08T07:11:19+00:00"
         },
+        {
+            "name": "jean85/pretty-package-versions",
+            "version": "2.0.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Jean85/pretty-package-versions.git",
+                "reference": "ae547e455a3d8babd07b96966b17d7fd21d9c6af"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Jean85/pretty-package-versions/zipball/ae547e455a3d8babd07b96966b17d7fd21d9c6af",
+                "reference": "ae547e455a3d8babd07b96966b17d7fd21d9c6af",
+                "shasum": ""
+            },
+            "require": {
+                "composer-runtime-api": "^2.0.0",
+                "php": "^7.1|^8.0"
+            },
+            "require-dev": {
+                "friendsofphp/php-cs-fixer": "^2.17",
+                "jean85/composer-provided-replaced-stub-package": "^1.0",
+                "phpstan/phpstan": "^0.12.66",
+                "phpunit/phpunit": "^7.5|^8.5|^9.4",
+                "vimeo/psalm": "^4.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Jean85\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Alessandro Lai",
+                    "email": "alessandro.lai85@gmail.com"
+                }
+            ],
+            "description": "A library to get pretty versions strings of installed dependencies",
+            "keywords": [
+                "composer",
+                "package",
+                "release",
+                "versions"
+            ],
+            "support": {
+                "issues": "https://github.com/Jean85/pretty-package-versions/issues",
+                "source": "https://github.com/Jean85/pretty-package-versions/tree/2.0.5"
+            },
+            "time": "2021-10-08T21:21:46+00:00"
+        },
         {
             "name": "justinrainbow/json-schema",
             "version": "v5.2.13",