Updates to 3rd party libraries

Add Dockerfile and specific docker-php.ini

inc/vendor/phpoffice/phpspreadsheet/tests/PhpSpreadsheetTests/Functional/MergedCellsTest.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Functional;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+class MergedCellsTest extends AbstractFunctional
+{
+    public function providerFormats()
+    {
+        return [
+            ['Html'],
+            ['Xls'],
+            ['Xlsx'],
+            ['Ods'],
+        ];
+    }
+
+    /**
+     * @dataProvider providerFormats
+     *
+     * @param string $format
+     */
+    public function testMergedCells($format)
+    {
+        $spreadsheet = new Spreadsheet();
+        $spreadsheet->setActiveSheetIndex(0);
+        $spreadsheet->getActiveSheet()->setCellValue('A1', '1');
+        $spreadsheet->getActiveSheet()->setCellValue('B1', '2');
+        $spreadsheet->getActiveSheet()->setCellValue('A2', '33');
+        $spreadsheet->getActiveSheet()->mergeCells('A2:B2');
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, $format);
+
+        $actual = 0;
+        foreach ($reloadedSpreadsheet->getWorksheetIterator() as $worksheet) {
+            $actual += count($worksheet->getMergeCells());
+        }
+
+        self::assertSame(1, $actual, "Format $format failed, could not read 1 merged cell");
+    }
+}