Enhancement: Allow using duration option for execution order

src/Util/Configuration.php

@@ -853,6 +853,10 @@ public function getPHPUnitConfiguration(): array
                     case 'no-depends':
                         $result['resolveDependencies'] = false;
 
+                        break;
+                    case 'duration':
+                        $result['executionOrder'] = TestSuiteSorter::ORDER_DURATION;
+
                         break;
                 }
             }

tests/end-to-end/execution-order/_files/order-by-duration.phpunit.xml

@@ -0,0 +1,11 @@
+<phpunit
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="../../../../phpunit.xsd"
+    executionOrder="duration"
+>
+    <testsuites>
+        <testsuite name="order-by-duration">
+            <directory>.</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

tests/end-to-end/execution-order/order-by-duration-via-phpunit-xml.phpt

@@ -0,0 +1,35 @@
+--TEST--
+phpunit --order-by=duration ./tests/end-to-end/execution-order/_files/TestWithDifferentDurations.php
+--FILE--
+<?php
+
+$tmpResultCache = tempnam(sys_get_temp_dir(), __FILE__);
+file_put_contents($tmpResultCache, file_get_contents(__DIR__ . '/_files/TestWithDifferentDurations.phpunit.result.cache.txt'));
+
+$phpunitXmlConfig = __DIR__ . '/_files/order-by-duration.phpunit.xml';
+
+$_SERVER['argv'][1] = '--configuration=' . $phpunitXmlConfig;
+$_SERVER['argv'][2] = '--debug';
+$_SERVER['argv'][4] = '--cache-result';
+$_SERVER['argv'][5] = '--cache-result-file=' . $tmpResultCache;
+$_SERVER['argv'][6] = 'TestWithDifferentDurations';
+$_SERVER['argv'][7] = __DIR__ . '/_files/TestWithDifferentDurations.php';
+
+require __DIR__ . '/../../bootstrap.php';
+PHPUnit\TextUI\Command::main();
+
+unlink($tmpResultCache);
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Test 'TestWithDifferentDurations::testTwo' started
+Test 'TestWithDifferentDurations::testTwo' ended
+Test 'TestWithDifferentDurations::testOne' started
+Test 'TestWithDifferentDurations::testOne' ended
+Test 'TestWithDifferentDurations::testThree' started
+Test 'TestWithDifferentDurations::testThree' ended
+
+
+Time: %s, Memory: %s
+
+OK (3 tests, 3 assertions)