fix: strip --processes from --list-tests when sharding in parallel

src/Plugins/Shard.php

@@ -204,7 +204,34 @@ private function allTests(array $arguments): array
      */
     private function removeParallelArguments(array $arguments): array
     {
-        return array_filter($arguments, fn (string $argument): bool => ! in_array($argument, ['--parallel', '-p'], strict: true));
+        $filtered = [];
+        $skipNext = false;
+
+        foreach ($arguments as $argument) {
+            if ($skipNext) {
+                $skipNext = false;
+
+                continue;
+            }
+
+            if (in_array($argument, ['--parallel', '-p'], strict: true)) {
+                continue;
+            }
+
+            if ($argument === '--processes') {
+                $skipNext = true;
+
+                continue;
+            }
+
+            if (str_starts_with($argument, '--processes=')) {
+                continue;
+            }
+
+            $filtered[] = $argument;
+        }
+
+        return $filtered;
     }
 
     /**

tests/Visual/Parallel.php

@@ -41,6 +41,12 @@
     expect($run('tests/Fixtures/Inheritance'))->toContain('Tests:    1 skipped, 1 passed (1 assertions)');
 })->skipOnWindows();
 
+test('a count-based shard runs in parallel when no shards file exists', function () use ($run) {
+    expect($run('tests/Fixtures/Inheritance', '--shard=1/1'))
+        ->toContain('Tests:    1 skipped, 1 passed (1 assertions)')
+        ->toContain('Parallel: 3 processes');
+})->skipOnWindows();
+
 test('parallel reports invalid datasets as failures', function () use ($run) {
     expect($run('tests/.tests/ParallelInvalidDataset'))
         ->toContain("A dataset with the name `missing.dataset` does not exist. You can create it using `dataset('missing.dataset', ['a', 'b']);`.")