Add support for test suite chunking directly in phpunit.

src/Runner/Filter/ChunkIterator.php

@@ -0,0 +1,78 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\Runner\Filter;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestSuite;
+use PHPUnit\Framework\WarningTestCase;
+use PHPUnit\Util\RegularExpression;
+use RecursiveFilterIterator;
+use RecursiveIterator;
+
+/**
+ * @internal This class is not covered by the backward compatibility promise for PHPUnit
+ */
+final class ChunkIterator extends RecursiveFilterIterator
+{
+    /**
+     * @var int
+     */
+    private $chunk;
+
+    /**
+     * @var int
+     */
+    private $numChunks;
+
+    /**
+     * @var Test[][]
+     */
+    private $chunks;
+
+    /**
+     * @throws \Exception
+     */
+    public function __construct(RecursiveIterator $iterator, array $args)
+    {
+        parent::__construct($iterator);
+
+        $this->chunk = $args['chunk'];
+        $this->numChunks = $args['numChunks'];
+
+        if ($this->chunk > $this->numChunks) {
+            throw new InvalidArgumentException(sprintf('You only configured %s chunks but passed chunk %s',
+                $this->numChunks,
+                $this->chunk
+            ));
+        }
+
+        $tests = iterator_to_array($iterator);
+        $numTests = count($tests);
+        $numTestsPerChunk = (int) round($numTests / $this->numChunks);
+
+        $this->chunks = array_chunk(iterator_to_array($iterator), $numTestsPerChunk);
+    }
+
+    public function accept(): bool
+    {
+        $chunkKey = $this->chunk - 1;
+
+        if (!isset($this->chunks[$chunkKey])) {
+            return false;
+        }
+
+        $chunk = $this->chunks[$chunkKey];
+
+        $test = $this->getInnerIterator()->current();
+
+        return in_array($test, $chunk, true);
+    }
+
+}

src/TextUI/Command.php

@@ -145,6 +145,8 @@ class Command
         'version'                   => null,
         'whitelist='                => null,
         'dump-xdebug-filter='       => null,
+        'chunk'                     => null,
+        'num-chunks'                => null,
     ];
 
     /**
@@ -765,6 +767,16 @@ protected function handleArguments(array $argv): void
 
                     break;
 
+                case '--chunk':
+                    $this->arguments['chunk'] = (int) $option[1];
+
+                    break;
+
+                case '--num-chunks':
+                    $this->arguments['num-chunks'] = (int) $option[1];
+
+                    break;
+
                 default:
                     $optionName = \str_replace('--', '', $option[0]);
 

src/TextUI/TestRunner.php

@@ -1248,6 +1248,16 @@ private function processSuiteFilters(TestSuite $suite, array $arguments): void
             );
         }
 
+        if (isset($arguments['chunk']) && $arguments['chunk']) {
+            $filterFactory->addFilter(
+                new ReflectionClass(ChunkIterator::class),
+                [
+                    'chunk' => $arguments['chunk'],
+                    'numChunks' => $arguments['num-chunk'] ?? 2,
+                ]
+            );
+        }
+
         $suite->injectFilter($filterFactory);
     }
 

tests/unit/Runner/Filter/ChunkIteratorTest.php

@@ -0,0 +1,112 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\Runner\Filter;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\TestSuite;
+
+class ChunkIteratorTest extends TestCase
+{
+    public function testChunkOne(): void
+    {
+        $tests = $this->getTestsChunk(1, 2);
+
+        $this->assertTrue(in_array(TestCase1Test::class.'::testTest', $tests));
+        $this->assertTrue(in_array(TestCase2Test::class.'::testTest', $tests));
+        $this->assertTrue(in_array(TestCase3Test::class.'::testTest', $tests));
+
+        $this->assertFalse(in_array(TestCase4Test::class.'::testTest', $tests));
+        $this->assertFalse(in_array(TestCase5Test::class.'::testTest', $tests));
+    }
+
+    public function testChunkTwo(): void
+    {
+        $tests = $this->getTestsChunk(2, 2);
+
+        $this->assertFalse(in_array(TestCase1Test::class.'::testTest', $tests));
+        $this->assertFalse(in_array(TestCase2Test::class.'::testTest', $tests));
+        $this->assertFalse(in_array(TestCase3Test::class.'::testTest', $tests));
+
+        $this->assertTrue(in_array(TestCase4Test::class.'::testTest', $tests));
+        $this->assertTrue(in_array(TestCase5Test::class.'::testTest', $tests));
+    }
+
+    public function testInvalidChunk(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('You only configured 2 chunks but passed chunk 3');
+
+        $tests = $this->getTestsChunk(3, 2);
+    }
+
+    /**
+     * @return TestCase[]
+     */
+    private function getTestsChunk(int $chunk, int $numChunks): array
+    {
+        $suite = new TestSuite;
+        $suite->addTest(new TestCase1Test('testTest'));
+        $suite->addTest(new TestCase2Test('testTest'));
+        $suite->addTest(new TestCase3Test('testTest'));
+        $suite->addTest(new TestCase4Test('testTest'));
+        $suite->addTest(new TestCase5Test('testTest'));
+
+        $iterator = new ChunkIterator($suite->getIterator(), [
+            'chunk' => $chunk,
+            'numChunks' => $numChunks,
+        ]);
+
+        $iterator->rewind();
+
+        $tests = [];
+
+        foreach ($iterator as $test) {
+            $tests[] = get_class($test).'::'.$test->getName();
+        }
+
+        return $tests;
+    }
+}
+
+class TestCase1Test extends TestCase
+{
+    public function testTest() : void
+    {
+    }
+}
+
+class TestCase2Test extends TestCase
+{
+    public function testTest() : void
+    {
+    }
+}
+
+class TestCase3Test extends TestCase
+{
+    public function testTest() : void
+    {
+    }
+}
+
+class TestCase4Test extends TestCase
+{
+    public function testTest() : void
+    {
+    }
+}
+
+class TestCase5Test extends TestCase
+{
+    public function testTest() : void
+    {
+    }
+}