Row objects and Cell styling

This commit introduces Row and Cell entities, that will replace the arrays passed in previously.
It also adds support for Cell styling (instead of Row styling only).

tests/Spout/Writer/Common/Entity/RowTest.php

@@ -0,0 +1,114 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Entity;
+
+use Box\Spout\Writer\Common\Entity\Style\Style;
+use Box\Spout\Writer\Common\Manager\RowManager;
+use PHPUnit\Framework\TestCase;
+
+class RowTest extends TestCase
+{
+    /**
+     * @return \PHPUnit_Framework_MockObject_MockObject|Style
+     */
+    private function getStyleMock()
+    {
+        return $this->createMock(Style::class);
+    }
+
+    /**
+     * @return \PHPUnit_Framework_MockObject_MockObject|Cell
+     */
+    private function getCellMock()
+    {
+        return $this->createMock(Cell::class);
+    }
+
+    /**
+     * @return \PHPUnit_Framework_MockObject_MockObject|RowManager
+     */
+    private function getRowManagerMock()
+    {
+        return $this->createMock(RowManager::class);
+    }
+
+    /**
+     * @return void
+     */
+    public function testValidInstance()
+    {
+        $this->assertInstanceOf(
+            Row::class,
+            new Row([], null, $this->getRowManagerMock())
+        );
+    }
+
+    /**
+     * @return void
+     */
+    public function testSetCells()
+    {
+        $row = new Row([], null, $this->getRowManagerMock());
+        $row->setCells([$this->getCellMock(), $this->getCellMock()]);
+
+        $this->assertEquals(2, count($row->getCells()));
+    }
+
+    /**
+     * @return void
+     */
+    public function testSetCellsResets()
+    {
+        $row = new Row([], null, $this->getRowManagerMock());
+        $row->setCells([$this->getCellMock(), $this->getCellMock()]);
+
+        $this->assertEquals(2, count($row->getCells()));
+
+        $row->setCells([$this->getCellMock()]);
+
+        $this->assertEquals(1, count($row->getCells()));
+    }
+
+    /**
+     * @return void
+     */
+    public function testGetCells()
+    {
+        $row = new Row([], null, $this->getRowManagerMock());
+
+        $this->assertEquals(0, count($row->getCells()));
+
+        $row->setCells([$this->getCellMock(), $this->getCellMock()]);
+
+        $this->assertEquals(2, count($row->getCells()));
+    }
+
+    /**
+     * @return void
+     */
+    public function testAddCell()
+    {
+        $row = new Row([], null, $this->getRowManagerMock());
+        $row->setCells([$this->getCellMock(), $this->getCellMock()]);
+
+        $this->assertEquals(2, count($row->getCells()));
+
+        $row->addCell($this->getCellMock());
+
+        $this->assertEquals(3, count($row->getCells()));
+    }
+
+    /**
+     * @return void
+     */
+    public function testFluentInterface()
+    {
+        $row = new Row([], null, $this->getRowManagerMock());
+        $row
+            ->addCell($this->getCellMock())
+            ->setStyle($this->getStyleMock())
+            ->setCells([]);
+
+        $this->assertTrue(is_object($row));
+    }
+}