Added some tests for important entity methods.

tests/Entity/PriceSystem/CurrencyTest.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony)
+ *
+ * Copyright (C) 2019 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Tests\Entity\PriceSystem;
+
+
+use App\Entity\PriceInformations\Currency;
+use PHPUnit\Framework\TestCase;
+
+class CurrencyTest extends TestCase
+{
+    public function testGetInverseExchangeRate()
+    {
+        $currency = new Currency();
+
+        //By default the inverse exchange rate is not set:
+        $this->assertNull($currency->getInverseExchangeRate());
+
+        $currency->setExchangeRate('0');
+        $this->assertNull($currency->getInverseExchangeRate());
+
+        $currency->setExchangeRate("1.45643");
+        $this->assertEquals("0.68661", $currency->getInverseExchangeRate());
+    }
+}