Expose Sheet::isActive() to provide info about the last active sheet (#405)

tests/Spout/Reader/ODS/SheetTest.php

@@ -18,15 +18,30 @@ class SheetTest extends \PHPUnit_Framework_TestCase
     /**
      * @return void
      */
-    public function testNextSheetShouldReturnCorrectSheetInfos()
+    public function testReaderShouldReturnCorrectSheetInfos()
     {
+        // NOTE: This spreadsheet has its second tab defined as active
         $sheets = $this->openFileAndReturnSheets('two_sheets_with_custom_names.ods');
 
         $this->assertEquals('Sheet First', $sheets[0]->getName());
         $this->assertEquals(0, $sheets[0]->getIndex());
+        $this->assertFalse($sheets[0]->isActive());
 
         $this->assertEquals('Sheet Last', $sheets[1]->getName());
         $this->assertEquals(1, $sheets[1]->getIndex());
+        $this->assertTrue($sheets[1]->isActive());
+    }
+
+    /**
+     * @return void
+     */
+    public function testReaderShouldDefineFirstSheetAsActiveByDefault()
+    {
+        // NOTE: This spreadsheet has no information about the active sheet
+        $sheets = $this->openFileAndReturnSheets('two_sheets_with_no_settings_xml_file.ods');
+
+        $this->assertTrue($sheets[0]->isActive());
+        $this->assertFalse($sheets[1]->isActive());
     }
 
     /**