add Emailer and EmailFactory interfaces with laravel + fake impls

backend/app/Email/EmailFactory.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Email;
+
+interface EmailFactory
+{
+    public function makeConfirmationEmail(string $token): string;
+}

backend/app/Email/Emailer.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Email;
+
+interface Emailer
+{
+    public function send(string $from, string $to, string $body): void;
+}

backend/app/Email/LaravelEmailFactory.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Email;
+
+class LaravelEmailFactory implements EmailFactory
+{
+    public function __construct(
+        private string $confirmationUrlPrefix,
+    ) {}
+
+    public function makeConfirmationEmail(string $token): string
+    {
+        return "Confirm your email: {$this->confirmationUrlPrefix}{$token}";
+    }
+}

backend/app/Email/LaravelMailer.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Email;
+
+use Illuminate\Contracts\Mail\Mailer;
+use Illuminate\Mail\Message;
+
+class LaravelMailer implements Emailer
+{
+    public function __construct(
+        private Mailer $mailer,
+    ) {}
+
+    public function send(string $from, string $to, string $body): void
+    {
+        $this->mailer->raw(
+            $body,
+            function (Message $message) use ($from, $to) {
+                $message->from($from)
+                    ->to($to)
+                    ->subject('TIDE');
+            }
+        );
+    }
+}

backend/tests/Fakes/FakeEmailFactory.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Tests\Fakes;
+
+use App\Email\EmailFactory;
+
+class FakeEmailFactory implements EmailFactory
+{
+    public function makeConfirmationEmail(string $token): string
+    {
+        return "confirm:{$token}";
+    }
+}

backend/tests/Fakes/FakeEmailer.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Tests\Fakes;
+
+use App\Email\Emailer;
+
+class FakeEmailer implements Emailer
+{
+    /**
+     * @var array<int, array{from: string, to: string, body: string}>
+     */
+    private array $sentEmails = [];
+
+    public function send(string $from, string $to, string $body): void
+    {
+        $this->sentEmails[] = [
+            'from' => $from,
+            'to' => $to,
+            'body' => $body,
+        ];
+    }
+
+    public function getNumberOfEmailsSent(): int
+    {
+        return count($this->sentEmails);
+    }
+
+    /**
+     * @return array<int, array{from: string, to: string, body: string}>
+     */
+    public function getSentEmails(): array
+    {
+        return $this->sentEmails;
+    }
+}