diff --git a/test.php b/test.php
new file mode 100644
index 0000000..a7fbdbf
--- /dev/null
+++ b/test.php
@@ -0,0 +1,114 @@
+<?php
+
+include_once 'src/Spout/Autoloader/autoload.php';
+
+use Box\Spout\Common\Type;
+use Box\Spout\Writer\WriterFactory;
+use Box\Spout\Writer\Style\StyleBuilder;
+use Box\Spout\Writer\Style\Color;
+
+# UNIX_DATE = (EXCEL_DATE - 25569) * 86400              : Excel -> unix
+# EXCEL_DATE = 25569 + (UNIX_DATE / 86400)              : Unix -> excel
+
+$test = function ($name, $sheets, $rows, $cols, $groupedRows = FALSE) {
+    $start = microtime(TRUE);
+    $writer = WriterFactory::create(Type::XLSX); // for XLSX files
+    $writer->openToFile('__'.$name.'.xlsx');
+
+    $styleDef = (new StyleBuilder())->setNumberFormat('0.00000')->build();
+    $styleRed = (new StyleBuilder())->setNumberFormat('[Red]0.00000')->build();
+    $styleDate = (new StyleBuilder())->setNumberFormat('d-mmm-YY HH:mm:ss')->build();
+    $writer->registerStyle($styleDef);
+    $writer->registerStyle($styleRed);
+    $writer->registerStyle($styleDate);
+
+    for ($sheetNum = 0; $sheetNum < $sheets; $sheetNum++) {
+        if ($sheetNum != 0) {
+            $sheet = $writer->addNewSheetAndMakeItCurrent();
+        } else {
+            $sheet = $writer->getCurrentSheet();
+        }
+        $sheet->setName('data'.$sheetNum);
+
+        $rowsArr = array();
+        for ($rowNum = 0; $rowNum < $rows; $rowNum++) {
+            $row = array();
+            for ($colNum = 0; $colNum < $cols; $colNum++) {
+                switch ($colNum % 6) {
+                    default:
+                        $row[] = $colNum;
+                    break;
+                    case 1:
+                    case 3:
+                        $row[] = array($colNum, $styleDef);
+                    break;
+                    case 2:
+                    case 4:
+                        $row[] = array($colNum, $styleRed);
+                    break;
+                    case 5:
+                        $row[] = array(25569 + (time() / 86400), $styleDate);
+                    break;
+                }
+            }
+
+            $rowsArr[] = $row;
+            if (!is_int($groupedRows)) {
+                $writer->addRow($row);
+                $rowsArr = array();
+            } else if (count($rowsArr) >= $groupedRows) {
+                $writer->addRows($rowsArr);
+                $rowsArr = array();
+            }
+        }
+
+        if (count($rowsArr)) {
+            $writer->addRows($rowsArr);
+        }
+    }
+
+    $writer->close();
+
+    $duration = number_format(microtime(TRUE) - $start, 2);
+    $str = sprintf(' %s took %s seconds to run (%d r/%d c in %d sheets)', $name, $duration, $rows, $cols, $sheets);
+    echo $str . PHP_EOL;
+};
+
+/**
+ * Bottleneck ATM: Disk usage
+ */
+
+$start_mem = memory_get_usage(TRUE);
+echo PHP_EOL."Memory Consumption is ";
+echo round($start_mem/1048576,2).''.' MB'.PHP_EOL;
+
+$test('1_mini_grouped_00000', 1, 50, 25, FALSE);
+
+exit (0);
+
+$cur_mem = memory_get_usage(TRUE);
+echo " Current Consumption is ";
+echo round($cur_mem/1048576,2).''.' MB'.PHP_EOL;
+
+$test('2_small_grouped_00000', 10, 7500, 50, FALSE);
+
+$cur_mem = memory_get_usage(TRUE);
+echo " Current Consumption is ";
+echo round($cur_mem/1048576,2).''.' MB'.PHP_EOL;
+
+$test('3_medium_grouped_00000', 10, 7500, 500, FALSE);
+
+$cur_mem = memory_get_usage(TRUE);
+echo " Current Consumption is ";
+echo round($cur_mem/1048576,2).''.' MB'.PHP_EOL;
+
+$test('4_large_grouped_00000', 10, 150000, 10000, FALSE);
+
+$cur_mem = memory_get_usage(TRUE);
+echo " Current Consumption is ";
+echo round($cur_mem/1048576,2).''.' MB'.PHP_EOL;
+
+echo " Peak Consumption is ";
+echo round(memory_get_peak_usage(TRUE)/1048576,2).''.' MB'.PHP_EOL;
+
+exit(0);
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