added annotation based exporter (#1831)

* added user exporter
* added project exporter
* added customer exporter
* added activity exporter

tests/Export/Spreadsheet/ColumnDefinitionTest.php

@@ -0,0 +1,30 @@
+<?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\Export\Spreadsheet;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \App\Export\Spreadsheet\ColumnDefinition
+ */
+class ColumnDefinitionTest extends TestCase
+{
+    public function testConstruct()
+    {
+        $sut = new \App\Export\Spreadsheet\ColumnDefinition('foo', 'bar', function () {
+            return 'hello world';
+        });
+
+        self::assertEquals('foo', $sut->getLabel());
+        self::assertEquals('bar', $sut->getType());
+        self::assertIsCallable($sut->getAccessor());
+        self::assertEquals('hello world', \call_user_func($sut->getAccessor()));
+    }
+}