Ensure that the directory doesn't already exist

app.php

@@ -0,0 +1,14 @@
+<?php
+
+use Opdavies\DrupalModuleGenerator\Command\GenerateDrupal7Command;
+use Symfony\Component\Console\Application;
+
+require_once __DIR__.'/vendor/autoload.php';
+
+$app = new Application();
+
+$app->addCommands([
+    new GenerateDrupal7Command(),
+]);
+
+$app->run();

composer.json

@@ -7,7 +7,9 @@
         "symfony/dependency-injection": "^5.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.0"
+        "php": "5.6 || ^7.0",
+        "phpunit/phpunit": "^9.0",
+        "symfony/var-dumper": "^5.0"
     },
     "license": "MIT",
     "authors": [
@@ -15,5 +17,18 @@
             "name": "Oliver Davies",
             "email": "oliver@oliverdavies.uk"
         }
-    ]
+    ],
+    "autoload": {
+        "psr-4": {
+            "Opdavies\\DrupalModuleGenerator\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Opdavies\\Tests\\DrupalModuleGenerator\\": "tests/"
+        }
+    },
+    "config": {
+        "sort-packages": true
+    }
 }

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": "c857126b9f1440b76b7f240733f85adb",
+    "content-hash": "21bd996a5a5331085c6854ddc3f384f2",
     "packages": [
         {
             "name": "psr/container",
@@ -1875,6 +1875,81 @@
             ],
             "time": "2019-11-27T13:56:44+00:00"
         },
+        {
+            "name": "symfony/var-dumper",
+            "version": "v5.0.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/var-dumper.git",
+                "reference": "923591cfb78a935f0c98968fedfad05bfda9d01f"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/var-dumper/zipball/923591cfb78a935f0c98968fedfad05bfda9d01f",
+                "reference": "923591cfb78a935f0c98968fedfad05bfda9d01f",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2.5",
+                "symfony/polyfill-mbstring": "~1.0"
+            },
+            "conflict": {
+                "phpunit/phpunit": "<5.4.3",
+                "symfony/console": "<4.4"
+            },
+            "require-dev": {
+                "ext-iconv": "*",
+                "symfony/console": "^4.4|^5.0",
+                "symfony/process": "^4.4|^5.0",
+                "twig/twig": "^2.4|^3.0"
+            },
+            "suggest": {
+                "ext-iconv": "To convert non-UTF-8 strings to UTF-8 (or symfony/polyfill-iconv in case ext-iconv cannot be used).",
+                "ext-intl": "To show region name in time zone dump",
+                "symfony/console": "To use the ServerDumpCommand and/or the bin/var-dump-server script"
+            },
+            "bin": [
+                "Resources/bin/var-dump-server"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "5.0-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "Resources/functions/dump.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Component\\VarDumper\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony mechanism for exploring and dumping PHP variables",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "debug",
+                "dump"
+            ],
+            "time": "2020-01-25T15:56:29+00:00"
+        },
         {
             "name": "theseer/tokenizer",
             "version": "1.1.3",
@@ -1970,5 +2045,7 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": [],
-    "platform-dev": []
+    "platform-dev": {
+        "php": "5.6 || ^7.0"
+    }
 }

phpunit.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit
+    bootstrap="vendor/autoload.php"
+    colors="true"
+>
+
+    <testsuites>
+        <testsuite name="Project Test Suite">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory suffix=".php">src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>

src/Command/GenerateDrupal7Command.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Opdavies\DrupalModuleGenerator\Command;
+
+use Opdavies\DrupalModuleGenerator\Exception\CannotCreateModuleException;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class GenerateDrupal7Command extends Command
+{
+    private $moduleName;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected static $defaultName = 'generate-drupal-7-module';
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function configure()
+    {
+        $this
+            ->setDescription('Generate a new Drupal 7 module.')
+            ->addArgument('module-name', InputArgument::REQUIRED, 'The name of the module to create');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $this->moduleName = $input->getArgument('module-name');
+
+        $this->ensureDirectoryDoesNotExist();
+
+        return 0;
+    }
+
+    /**
+     * Ensure that the directory name for the module doesn't already exist.
+     */
+    private function ensureDirectoryDoesNotExist()
+    {
+        if (is_dir($this->moduleName)) {
+            throw CannotCreateModuleException::directoryAlreadyExists();
+        }
+    }
+}

src/Exception/CannotCreateModuleException.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Opdavies\DrupalModuleGenerator\Exception;
+
+class CannotCreateModuleException extends \RuntimeException
+{
+    public static function directoryAlreadyExists()
+    {
+        return new static('The given directory name for the module already exists.');
+    }
+}

tests/Command/GenerateDrupal7ModuleCommandTest.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Opdavies\Tests\DrupalModuleGenerator\Command;
+
+use Opdavies\DrupalModuleGenerator\Command\GenerateDrupal7Command;
+use Opdavies\DrupalModuleGenerator\Exception\CannotCreateModuleException;
+use Symfony\Component\Console\Tester\CommandTester;
+use PHPUnit\Framework\TestCase;
+
+class GenerateDrupal7ModuleCommandTest extends TestCase
+{
+    /** @test */
+    public function it_throws_an_exception_if_the_directory_already_exists() {
+        mkdir('my-existing-drupal-module');
+
+        try {
+            $commandTester = new CommandTester(new GenerateDrupal7Command());
+            $commandTester->execute([
+                'module-name' => 'my-existing-drupal-module',
+            ]);
+        } catch (CannotCreateModuleException $e) {
+            $this->addToAssertionCount(1);
+        }
+
+        rmdir('my-existing-drupal-module');
+    }
+}