Refactor the User validator.

tests/Feature/Validation/UserValidationTest.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace Tests\Feature;
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Foundation\Testing\WithFaker;
+use Tests\TestCase;
+
+use Illuminate\Http\Request;
+
+use App\Models\User;
+
+class UserValidationTest extends TestCase
+{
+    public function testEmptyUsernameWithMatrixUsername(): void
+    {
+        $json = User::validateWithMatrixUsername('');
+
+        $this->assertEquals($json['error'], 'The username is empty, please, write username!!!');
+    }
+
+    public function testValidUserWithMatrixUsername(): void
+    {
+        $matrixUsername = '@test:test.com';
+
+        $json = User::validateWithMatrixUsername($matrixUsername);
+
+        $this->assertEquals($json['ok'], 'A user with the username is valid.');
+    }
+
+    public function testNotExistingUserWithMatrixUsername(): void
+    {
+        $matrixUsername = '@kostia:test.com';
+
+        $json = User::validateWithMatrixUsername($matrixUsername);
+
+        $this->assertEquals($json['error'], 'A user with the username does not exist!!!');
+    }
+}