feat: Implement user management functionality with impersonation support

tests/Domain/Users/UserRepositoryTest.php

@@ -0,0 +1,53 @@
+<?php
+
+require_once __DIR__ . '/../../../autoload/Domain/Users/UserRepository.php';
+
+use Domain\Users\UserRepository;
+
+class FakeUsersMdb
+{
+  public $last_select = [];
+  public $last_get = [];
+  private $rows = [];
+
+  public function __construct( array $rows )
+  {
+    $this -> rows = $rows;
+  }
+
+  public function select( $table, $columns, $where )
+  {
+    $this -> last_select = [ 'table' => $table, 'columns' => $columns, 'where' => $where ];
+    return $this -> rows;
+  }
+
+  public function get( $table, $columns, $where )
+  {
+    $this -> last_get = [ 'table' => $table, 'columns' => $columns, 'where' => $where ];
+    foreach ( $this -> rows as $row )
+    {
+      if ( (int)$row['id'] === (int)$where['id'] )
+        return $row;
+    }
+    return false;
+  }
+}
+
+function run_user_repository_tests()
+{
+  $rows = [
+    [ 'id' => 1, 'email' => 'admin@example.com', 'name' => 'Admin', 'surname' => 'User' ],
+    [ 'id' => 3, 'email' => 'user@example.com', 'name' => 'Normal', 'surname' => 'User' ]
+  ];
+
+  $fake_mdb = new FakeUsersMdb( $rows );
+  $repository = new UserRepository( $fake_mdb );
+
+  $all = $repository -> all();
+  assert_true( count( $all ) === 2, 'Expected all() to return all users.' );
+  assert_true( $fake_mdb -> last_select['table'] === 'users', 'Expected all() to query users table.' );
+
+  $user = $repository -> byId( 3 );
+  assert_true( (int)$user['id'] === 3, 'Expected byId() to return matching user.' );
+  assert_true( (int)$fake_mdb -> last_get['where']['id'] === 3, 'Expected byId() to query requested id.' );
+}