Daniel-Marynicz · Daniel-Marynicz · Jan 20, 2026 · Jan 19, 2026
diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
@@ -84,6 +84,6 @@ jobs:
     # Add a test script to composer.json, for instance: "test": "vendor/bin/phpunit"
     # Docs: https://getcomposer.org/doc/articles/scripts.md
     - name: Run PHPUnit
-      run: ./vendor/bin/phpunit --fail-on-warning
+      run: composer phpunit
     - name: Run Behat
-      run: ./vendor/bin/behat --colors --strict --stop-on-failure
+      run: composer behat
diff --git a/.gitignore b/.gitignore
@@ -2,4 +2,5 @@
 /.phpcs-cache
 /.phpunit.result.cache
 /test.json
-/composer.lock
+/tests/fixtures/*/chunk_test.json
+/composer.lock
diff --git a/README.md b/README.md
@@ -18,15 +18,15 @@ If you Properly integrate your app with this extension then it can be dramatical
 * Extension can cancel your tests when you hit CTRL+C.
 * When you have failed tests in **Parallel scenario** mode then can you rerun this test with Behat option `--rerun`.
 * For each worker you can set environment variables.
+* You can group scenarios or features into a single job to improve test execution time by using the same kernel bootstrapped once.
 
 ### Main modes
 
 Behat Parallel Extension can work in two main modes:
 
 * **Parallel scenario** witch can be enabled by option `--parallel` or  `-l`.
 * **Parallel feature** to enable this you need use behat option `--parallel-feature`.
-
- Parallel feature option does not support's `--rerun` option.
+- **Parallel chunk size** to group multiple scenarios or features into a single job, use the --parallel-chunk-size option (default is 1). Only available with Behat >= 3.23
 
 ## Requirements
 
@@ -159,25 +159,44 @@ Use `--parallel` or `-l` option for start in parallel scenario mode.
 
   ```
   $ vendor/bin/behat -l 8 --colors
-  Starting parallel scenario tests with 8 workers
+  Starting parallel tests with 8 workers
    Feature: Parallel
     Scenario: Test behat tests with failed result
    3/3 [============================] 100% 12 secs/12 secs
   ```
 
   ```
   $ vendor/bin/behat --parallel-feature 8 --colors
-  Starting parallel scenario tests with 8 workers
+  Starting parallel tests with 8 workers
    Feature: Parallel
-    Scenario: Test behat tests with failed result
+
    3/3 [============================] 100% 12 secs/12 secs
   ```
 
-## Test with the oldest supported PHP version
+  ```
+  $ vendor/bin/behat --parallel 8 --colors --parallel-chunk-size 2
+  Starting parallel tests with 8 workers
+   Feature: Parallel, Any other feature
+    Scenario: Test behat tests with failed result, Any other scenario
+   3/3 [============================] 100% 12 secs/12 secs
+  ```
+
+## Test with the oldest supported PHP version and oldest vendors
+
+With docker, without Dockerfile:
 
 ```bash
-composer update --prefer-lowest --prefer-stable
-docker run --rm -ti -v $(pwd):/app -w /app -u $(id -u):$(id -g) php:7.4-cli bash -c "vendor/bin/phpunit; vendor/bin/behat"
+# Create the docker container
+docker run --rm -d -v $(pwd):/app -w /app --name behat-parallel-old-php php:7.4-cli bash -c "tail -f /dev/null"
+# Install deps
+docker exec -ti behat-parallel-old-php bash -c "apt-get update && apt-get install -y libzip-dev && docker-php-ext-install zip"
+# Install composer for the current user
+docker exec -ti -u $(id -u):$(id -g) -e HOME=/tmp behat-parallel-old-php bash -c "curl -s https://getcomposer.org/installer | php -- --install-dir=/tmp; php /tmp/composer.phar update --prefer-lowest --prefer-dist;"
+# Run tests
+docker exec -ti -u $(id -u):$(id -g) behat-parallel-old-php php /tmp/composer.phar phpunit
+docker exec -ti -u $(id -u):$(id -g) behat-parallel-old-php php /tmp/composer.phar behat
+# Stop and remove the docker container
+docker kill behat-parallel-old-php
 ```
 
 ## Tools and Coding standards

diff --git a/behat.yml.dist b/behat.yml.dist
@@ -14,4 +14,4 @@ default:
                 - DMarynicz\Tests\Behat\Context\SimulateTestContext
     extensions:
         DMarynicz\BehatParallelExtension\Extension: ~
-
+        DMarynicz\Tests\Behat\Extension\TestsSkipperExtension: ~
diff --git a/features/chunk-size.feature b/features/chunk-size.feature
@@ -0,0 +1,132 @@
+@skip_without_multiple_paths
+Feature: Parallel chunk size parameter
+  As a programmer, I want to able to group my tests in chunks to reduce overhead.
+
+  Scenario: Test behat tests with --parallel-chunk-size and --parallel-feature option
+    Given I delete file "tests/fixtures/chunked/chunk_test.json"
+    When I run "behat --config tests/fixtures/chunked/behat.yml.dist --parallel-feature 20 --parallel-chunk-size 2"
+    Then it should pass
+    And I should see progress bar
+    And the output should contain:
+    """
+    Starting parallel tests with 20 workers and 2 tests per worker
+    """
+    # suite01 has 2 features -> should be 1 chunk containing both
+    # suite02 has 1 feature -> should be 1 chunk
+    # Total 2 commands expected
+    And I should have 2 behat commands in "tests/fixtures/chunked/chunk_test.json"
+    Then behat commands in "tests/fixtures/chunked/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite01/f1.feature tests/fixtures/chunked/suite01/f2.feature
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite02/f3.feature
+      """
+
+  Scenario: Test behat tests with --parallel-chunk-size and --parallel option
+    Given I delete file "tests/fixtures/chunked/chunk_test.json"
+    When I run "behat --config tests/fixtures/chunked/behat.yml.dist --parallel 20 --parallel-chunk-size 2"
+    Then it should pass
+    And I should see progress bar
+    And the output should contain:
+    """
+    Starting parallel tests with 20 workers and 2 tests per worker
+    """
+    # suite01: f1 (1 scenario), f2 (1 scenario) -> 2 scenarios total -> 1 chunk
+    # suite02: f3 (2 scenarios) -> 2 scenarios -> 1 chunk
+    # Total 2 commands expected
+    And I should have 2 behat commands in "tests/fixtures/chunked/chunk_test.json"
+    Then behat commands in "tests/fixtures/chunked/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite01/f1.feature:2 tests/fixtures/chunked/suite01/f2.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite02/f3.feature:2 tests/fixtures/chunked/suite02/f3.feature:4
+      """
+
+  Scenario: Test behat tests with --parallel-chunk-size 1 (default)
+    Given I delete file "tests/fixtures/chunked/chunk_test.json"
+    When I run "behat --config tests/fixtures/chunked/behat.yml.dist --parallel 20"
+    Then it should pass
+    And I should see progress bar
+    And the output should contain:
+    """
+    Starting parallel tests with 20 workers
+    """
+    # 3 features total, 4 scenarios total
+    # suite01: f1 (1 scenario), f2 (1 scenario)
+    # suite02: f3 (2 scenarios)
+    # Total 4 scenarios -> 4 commands
+    And I should have 4 behat commands in "tests/fixtures/chunked/chunk_test.json"
+    Then behat commands in "tests/fixtures/chunked/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite01/f1.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite01/f2.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite02/f3.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite02/f3.feature:4
+      """
+
+  Scenario: Test behat tests with --rerun and --parallel-chunk-size 2
+    Given I delete file "tests/fixtures/chunked/chunk_test.json"
+    # Rerun should still execute chunked tasks when no previous failures exist.
+    When I run "behat --config tests/fixtures/chunked/behat.yml.dist --parallel 2 --parallel-chunk-size 2 --rerun"
+    Then it should pass
+    And I should see progress bar
+    And the output should contain:
+      """
+      Starting parallel tests with 2 workers and 2 tests per worker
+      """
+    And I should have 2 behat commands in "tests/fixtures/chunked/chunk_test.json"
+    Then behat commands in "tests/fixtures/chunked/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --rerun --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite01/f1.feature:2 tests/fixtures/chunked/suite01/f2.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --rerun --config tests/fixtures/chunked/behat.yml.dist tests/fixtures/chunked/suite02/f3.feature:2 tests/fixtures/chunked/suite02/f3.feature:4
+      """
+
+  Scenario: Test behat tests with --rerun and one failing job with --parallel option
+    Given I delete file "tests/fixtures/chunked_rerun/chunk_test.json"
+    # First run executes at least two chunks from suite01.
+    And I run "behat --config tests/fixtures/chunked_rerun/behat.yml.dist --parallel 2 --parallel-chunk-size 2"
+    Then it should fail
+    And I should have 2 behat commands in "tests/fixtures/chunked_rerun/chunk_test.json"
+    And behat commands in "tests/fixtures/chunked_rerun/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f1.feature:2 tests/fixtures/chunked_rerun/suite01/f2.feature:2
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f3.feature:2
+      """
+    And I delete file "tests/fixtures/chunked_rerun/chunk_test.json"
+    # Rerun only the previously failed command from suite01.
+    When I run "behat --config tests/fixtures/chunked_rerun/behat.yml.dist --parallel 2 --parallel-chunk-size 2 --rerun"
+    Then it should fail
+    And I should see progress bar
+    And the output should contain:
+      """
+      Starting parallel tests with 2 workers and 2 tests per worker
+      """
+    And I should have 1 behat commands in "tests/fixtures/chunked_rerun/chunk_test.json"
+    And behat commands in "tests/fixtures/chunked_rerun/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --rerun --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f1.feature:2 tests/fixtures/chunked_rerun/suite01/f2.feature:2
+      """
+
+  Scenario: Test behat tests with --rerun and one failing job with --parallel-feature option
+    Given I delete file "tests/fixtures/chunked_rerun/chunk_test.json"
+    # First run executes at least two chunks from suite01.
+    And I run "behat --config tests/fixtures/chunked_rerun/behat.yml.dist --parallel-feature 2 --parallel-chunk-size 2"
+    Then it should fail
+    And I should have 2 behat commands in "tests/fixtures/chunked_rerun/chunk_test.json"
+    And behat commands in "tests/fixtures/chunked_rerun/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f1.feature tests/fixtures/chunked_rerun/suite01/f2.feature
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f3.feature
+      """
+    And I delete file "tests/fixtures/chunked_rerun/chunk_test.json"
+    # Rerun only the previously failed command from suite01.
+    When I run "behat --config tests/fixtures/chunked_rerun/behat.yml.dist --parallel-feature 2 --parallel-chunk-size 2 --rerun"
+    Then it should fail
+    And I should see progress bar
+    And the output should contain:
+      """
+      Starting parallel tests with 2 workers and 2 tests per worker
+      """
+    And I should have 1 behat commands in "tests/fixtures/chunked_rerun/chunk_test.json"
+    And behat commands in "tests/fixtures/chunked_rerun/chunk_test.json" should match:
+      """
+      {BEHAT_BIN} --no-interaction --fail-on-undefined-step --rerun --config tests/fixtures/chunked_rerun/behat.yml.dist tests/fixtures/chunked_rerun/suite01/f1.feature tests/fixtures/chunked_rerun/suite01/f2.feature
+      """
diff --git a/features/environment.feature b/features/environment.feature
@@ -7,7 +7,7 @@ Feature: Environment
     Then it should pass
     And the output should contain:
     """
-    Starting parallel scenario tests with 8 workers
+    Starting parallel tests with 8 workers
     """
     And the output should contain:
     """

diff --git a/features/parallel-feature-environment.feature b/features/parallel-feature-environment.feature
@@ -7,7 +7,7 @@ Feature: Environment
     Then it should pass
     And the output should contain:
     """
-    Starting parallel scenario tests with 8 workers
+    Starting parallel tests with 8 workers
     """
     And the output should contain:
     """

diff --git a/features/sigint.feature b/features/sigint.feature
@@ -7,4 +7,4 @@ Feature: Sigint
     Given I start "behat --config tests/fixtures/fail/behat.yml.dist  --parallel 2"
     And I wait for 3 seconds
     And I send a SIGINT signal to behat process
-    Then it should fail
+    Then it should fail
diff --git a/src/Cli/ParallelController.php b/src/Cli/ParallelController.php
@@ -2,7 +2,6 @@
 
 namespace DMarynicz\BehatParallelExtension\Cli;
 
-use Behat\Gherkin\Node\ScenarioLikeInterface;
 use Behat\Testwork\Cli\Controller;
 use Behat\Testwork\Tester\Cli\ExerciseController;
 use DMarynicz\BehatParallelExtension\Event\AfterTaskTested;
@@ -52,6 +51,9 @@ abstract class ParallelController
     /** @var CanDetermineNumberOfProcessingUnits */
     protected $numberOfCores;
 
+    /** @var TitleListFormatter */
+    protected $titleListFormatter;
+
     public function __construct(
         Controller $decoratedController,
         TaskFactory $taskFactory,
@@ -86,20 +88,20 @@ public function execute(InputInterface $input, OutputInterface $output)
         $this->output = $output;
         $this->input  = $input;
 
+        // Unable to get the COLUMNS environment variable to know the width of the terminal
+        // because Behat overrides it to 9999. Let's use the default TitleListFormatter's maxLength value.
+        $this->titleListFormatter = new TitleListFormatter();
+
         return $this->parallelExecute();
     }
 
     public function beforeTaskTested(BeforeTaskTested $beforeTaskTested): void
     {
-        $task          = $beforeTaskTested->getTask();
-        $featureTitle  = sprintf('<info>Feature: %s</info>', $task->getFeature()->getTitle());
-        $scenarioTitle = '';
-        if ($task->getScenario() instanceof ScenarioLikeInterface) {
-            $scenarioTitle = sprintf('<info>Scenario: %s</info>', $task->getScenario()->getTitle());
-        }
+        $task  = $beforeTaskTested->getTask();
+        $units = $task->getUnits();
 
-        $this->progressBar->setMessage($featureTitle, 'feature');
-        $this->progressBar->setMessage($scenarioTitle, 'scenario');
+        $this->progressBar->setMessage($this->titleListFormatter->formatFeatures($units), 'feature');
+        $this->progressBar->setMessage($this->titleListFormatter->formatScenarios($units), 'scenario');
     }
 
     public function afterTaskTested(AfterTaskTested $taskTested): void
@@ -168,8 +170,17 @@ private function setupTasksWithProgressBar(): void
 
     private function startPoll(): void
     {
-        $poolSize = $this->getMaxPoolSize();
-        $this->output->writeln(sprintf('Starting parallel scenario tests with %d workers', $poolSize));
+        $poolSize  = $this->getMaxPoolSize();
+        $chunkSize = (int) $this->input->getOption('parallel-chunk-size');
+        $message   = sprintf(
+            'Starting parallel tests with %d workers',
+            $poolSize
+        );
+        if ($chunkSize > 1) {
+            $message .= sprintf(' and %d tests per worker', $chunkSize);
+        }
+
+        $this->output->writeln($message);
         $this->poll->setMaxWorkers($poolSize);
         $this->poll->start();
         $maxSize = $this->getMaxSizeFromParallelOption();
@@ -204,12 +215,12 @@ private function createTasks()
             return $this->taskFactory->createTasks($this->input, null);
         }
 
-        $tasks = [];
+        $tasksPerPath = [];
         foreach ($paths as $path) {
-            $tasks = array_merge($tasks, $this->taskFactory->createTasks($this->input, $path));
+            $tasksPerPath[] = $this->taskFactory->createTasks($this->input, $path);
         }
 
-        return $tasks;
+        return array_merge(...$tasksPerPath);
     }
 
     /**

diff --git a/src/Cli/ParallelFeatureController.php b/src/Cli/ParallelFeatureController.php
@@ -20,6 +20,13 @@ public function configure(SymfonyCommand $command): void
             'How many scenario jobs run in parallel feature mode? Available values empty or integer',
             false
         );
+        $command->addOption(
+            'parallel-chunk-size',
+            null,
+            InputOption::VALUE_OPTIONAL,
+            'How many features run in one chunk? (Behat >= 3.23)',
+            1
+        );
     }
 
     /**

diff --git a/src/Cli/ParallelScenarioController.php b/src/Cli/ParallelScenarioController.php
@@ -22,6 +22,13 @@ public function configure(SymfonyCommand $command): void
         )
             ->addUsage('--parallel 8')
             ->addUsage('--parallel');
+        $command->addOption(
+            'parallel-chunk-size',
+            null,
+            InputOption::VALUE_OPTIONAL,
+            'How many scenarios run in one chunk? (Behat >= 3.23)',
+            1
+        );
     }
 
     /**

diff --git a/src/Cli/RerunController.php b/src/Cli/RerunController.php
@@ -3,7 +3,6 @@
 namespace DMarynicz\BehatParallelExtension\Cli;
 
 use Behat\Behat\Tester\Cli\RerunController as BehatRerunController;
-use Behat\Gherkin\Node\ScenarioLikeInterface;
 use Behat\Testwork\Cli\Controller;
 use DMarynicz\BehatParallelExtension\Event\AfterTaskTested;
 use DMarynicz\BehatParallelExtension\Event\EventDispatcherDecorator;
@@ -59,20 +58,18 @@ public function collectFailedTask(AfterTaskTested $taskTested): void
             return;
         }
 
-        $suiteName    = $taskTested->getTask()->getSuite()->getName();
-        $featureFile  = $taskTested->getTask()->getFeature()->getFile();
-        $scenarioLine = null;
-        $scenario     = $taskTested->getTask()->getScenario();
-        if ($scenario instanceof ScenarioLikeInterface) {
-            $scenarioLine = $scenario->getLine();
-        }
+        $task      = $taskTested->getTask();
+        $suiteName = $task->getSuite()->getName();
+        $units     = $task->getUnits();
 
-        $line = $featureFile;
-        if ($scenarioLine !== null) {
-            $line .= ':' . $scenarioLine;
-        }
+        foreach ($units as $unit) {
+            $path = $unit->getPath();
+            if (in_array($path, $this->lines[$suiteName] ?? [], true)) {
+                continue;
+            }
 
-        $this->lines[$suiteName][] = $line;
+            $this->lines[$suiteName][] = $path;
+        }
     }
 
     /**