feat() formula support see #612

tests/Spout/Writer/XLSX/FormulaTest.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX;
+
+
+use Box\Spout\Common\Type;
+use Box\Spout\Reader\ReaderFactory;
+use Box\Spout\Reader\XLSX\Sheet;
+use Box\Spout\TestUsingResource;
+use Box\Spout\Writer\WriterFactory;
+
+class FormulaTest extends \PHPUnit_Framework_TestCase
+{
+
+    use TestUsingResource;
+
+    /**
+     * @throws \Box\Spout\Common\Exception\IOException
+     * @throws \Box\Spout\Common\Exception\UnsupportedTypeException
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException
+     * @throws \Box\Spout\Common\Exception\InvalidArgumentException
+     * @throws \Box\Spout\Reader\Exception\ReaderNotOpenedException
+     */
+    public function testGetXml()
+    {
+        $fileName = 'test_formula.xlsx';
+        $this->createGeneratedFolderIfNeeded($fileName);
+        $resourcePath = $this->getGeneratedResourcePath($fileName);
+
+        $writer = WriterFactory::create(Type::XLSX);
+        $writer->openToFile($resourcePath);
+
+        $writer->addRows([
+            [1],
+            [1],
+            [1],
+            [1],
+        ]);
+
+        $writer->addRow([
+            new Formula('SUM(A1:A4)', 4)
+        ]);
+        $writer->close();
+
+
+        $reader = ReaderFactory::create(Type::XLSX);
+        $reader->open($resourcePath);
+
+        $i = 0;
+        /** @var Sheet $sheet */
+        foreach ($reader->getSheetIterator() as $sheet) {
+            foreach ($sheet->getRowIterator() as $item) {
+                $i++;
+                if ($i == 5) {
+                    static::assertEquals(4, $item[0]);
+                }
+            }
+        }
+    }
+}