feat(test): add test for command list user

The command list user was not tested until now, and that's quite sad
because it's one of the only part of the code that actually sends an
email. Symfony has some tools for testing emails, let's use them!

I also refactored a little bit command testing since there was identical
code between test cases. (intantiating the command)

Author: Nek-

tests/Command/AbstractCommandTest.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Command;
+
+use Symfony\Bundle\FrameworkBundle\Console\Application;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\Console\Tester\CommandTester;
+
+abstract class AbstractCommandTest extends KernelTestCase
+{
+    protected function setUp(): void
+    {
+        exec('stty 2>&1', $output, $exitcode);
+        $isSttySupported = 0 === $exitcode;
+
+        if ('Windows' === PHP_OS_FAMILY || !$isSttySupported) {
+            $this->markTestSkipped('`stty` is required to test this command.');
+        }
+    }
+
+    /**
+     * This helper method abstracts the boilerplate code needed to test the
+     * execution of a command.
+     *
+     * @param array $arguments All the arguments passed when executing the command
+     * @param array $inputs    The (optional) answers given to the command when it asks for the value of the missing arguments
+     */
+    protected function executeCommand(array $arguments, array $inputs = []): CommandTester
+    {
+        self::bootKernel();
+
+        // this uses a special testing container that allows you to fetch private services
+        $command = self::$container->get($this->getCommandFqcn());
+        $command->setApplication(new Application(self::$kernel));
+
+        $commandTester = new CommandTester($command);
+        $commandTester->setInputs($inputs);
+        $commandTester->execute($arguments);
+
+        return $commandTester;
+    }
+
+    abstract protected function getCommandFqcn(): string;
+}

tests/Command/AddUserCommandTest.php

@@ -13,11 +13,8 @@
 
 use App\Command\AddUserCommand;
 use App\Repository\UserRepository;
-use Symfony\Bundle\FrameworkBundle\Console\Application;
-use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
-use Symfony\Component\Console\Tester\CommandTester;
 
-class AddUserCommandTest extends KernelTestCase
+class AddUserCommandTest extends AbstractCommandTest
 {
     private $userData = [
         'username' => 'chuck_norris',
@@ -26,16 +23,6 @@ class AddUserCommandTest extends KernelTestCase
         'full-name' => 'Chuck Norris',
     ];
 
-    protected function setUp(): void
-    {
-        exec('stty 2>&1', $output, $exitcode);
-        $isSttySupported = 0 === $exitcode;
-
-        if ('Windows' === PHP_OS_FAMILY || !$isSttySupported) {
-            $this->markTestSkipped('`stty` is required to test this command.');
-        }
-    }
-
     /**
      * @dataProvider isAdminDataProvider
      *
@@ -102,23 +89,8 @@ private function assertUserCreated(bool $isAdmin): void
         $this->assertSame($isAdmin ? ['ROLE_ADMIN'] : ['ROLE_USER'], $user->getRoles());
     }
 
-    /**
-     * This helper method abstracts the boilerplate code needed to test the
-     * execution of a command.
-     *
-     * @param array $arguments All the arguments passed when executing the command
-     * @param array $inputs    The (optional) answers given to the command when it asks for the value of the missing arguments
-     */
-    private function executeCommand(array $arguments, array $inputs = []): void
+    protected function getCommandFqcn(): string
     {
-        self::bootKernel();
-
-        // this uses a special testing container that allows you to fetch private services
-        $command = self::$container->get(AddUserCommand::class);
-        $command->setApplication(new Application(self::$kernel));
-
-        $commandTester = new CommandTester($command);
-        $commandTester->setInputs($inputs);
-        $commandTester->execute($arguments);
+        return AddUserCommand::class;
     }
 }

tests/Command/ListUsersCommandTest.php

@@ -0,0 +1,64 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Command;
+
+use App\Command\ListUsersCommand;
+
+class ListUsersCommandTest extends AbstractCommandTest
+{
+    /**
+     * @dataProvider maxResultsProvider
+     *
+     * This test verifies the amount of data is right according to the given parameter max results.
+     */
+    public function testListUsers(int $maxResults): void
+    {
+        $tester = $this->executeCommand(
+            ['--max-results' => $maxResults]
+        );
+
+        $emptyDisplayLines = 5;
+        $this->assertSame($emptyDisplayLines + $maxResults, mb_substr_count($tester->getDisplay(), "\n"));
+    }
+
+    public function maxResultsProvider(): ?\Generator
+    {
+        yield [1];
+        yield [2];
+    }
+
+    /**
+     * @dataProvider sendEmailProvider
+     *
+     * This test ensure that the command actually sends an email when the parameter is specified
+     */
+    public function testItSendsAnEmail(bool $sendAndEmail): void
+    {
+        $this->executeCommand(
+            // these are the arguments (only 1 is passed, the rest are missing)
+            $sendAndEmail ? ['--send-to' => 'john.doe@symfony.com'] : []
+        );
+
+        $this->assertEmailCount($sendAndEmail ? 1 : 0);
+    }
+
+    public function sendEmailProvider(): ?\Generator
+    {
+        yield [true];
+        yield [false];
+    }
+
+    protected function getCommandFqcn(): string
+    {
+        return ListUsersCommand::class;
+    }
+}