adds tests for logging in with a guest user

Author: daftspunk

tests/AuthManagerTest.php

@@ -112,4 +112,38 @@ public function testLoginAndCheckAuth()
 
         $this->assertTrue(Auth::check());
     }
+
+    /**
+     * testLoginAfterRegisteringWithSharedGuestEmail verifies the scenario reported
+     * in rainlab/user-plugin#544: after a guest exists for an email, a real
+     * registration succeeds and credential lookup resolves to the registered
+     * account, not the guest.
+     */
+    public function testLoginAfterRegisteringWithSharedGuestEmail()
+    {
+        $guest = User::create([
+            'first_name' => 'Guest',
+            'email' => 'person@acme.tld',
+            'is_guest' => true,
+        ]);
+
+        $registered = User::create([
+            'first_name' => 'Registered',
+            'email' => 'person@acme.tld',
+            'password' => 'ChangeMe888',
+            'password_confirmation' => 'ChangeMe888',
+        ]);
+
+        $this->assertEquals(2, User::where('email', 'person@acme.tld')->count());
+        $this->assertTrue($guest->is_guest);
+        $this->assertFalse((bool) $registered->is_guest);
+
+        $found = Auth::attempt([
+            'email' => 'person@acme.tld',
+            'password' => 'ChangeMe888',
+        ]);
+
+        $this->assertTrue($found);
+        $this->assertEquals($registered->id, Auth::user()->id);
+    }
 }