added invoice delete event (#3096)

tests/Event/InvoiceDeleteEventTest.php

@@ -0,0 +1,29 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Event;
+
+use App\Entity\Invoice;
+use App\Event\InvoiceDeleteEvent;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \App\Event\InvoiceDeleteEvent
+ */
+class InvoiceDeleteEventTest extends TestCase
+{
+    public function testDefaultValues()
+    {
+        $invoice = new Invoice();
+
+        $sut = new InvoiceDeleteEvent($invoice);
+
+        self::assertSame($invoice, $sut->getInvoice());
+    }
+}