trait TestRequirementsTrait

trait TestRequirementsTrait {
    
    /**
     * Returns the Drupal root directory.
     *
     * @return string
     */
    protected static function getDrupalRoot() {
        return dirname(substr(__DIR__, 0, -strlen(__NAMESPACE__)), 2);
    }
    
    /**
     * Check module requirements for the Drupal use case.
     *
     * This method is assumed to override
     * \PHPUnit\Framework\TestCase::checkRequirements().
     *
     * @throws \PHPUnit\Framework\SkippedTestError
     *   Thrown when the requirements are not met, and this test should be
     *   skipped. Callers should not catch this exception.
     */
    protected function checkRequirements() {
        if (!$this->getName(FALSE) || !method_exists($this, $this->getName(FALSE))) {
            return;
        }
        $missingRequirements = Test::getMissingRequirements(static::class, $this->getName(FALSE));
        if (!empty($missingRequirements)) {
            $this->markTestSkipped(implode(PHP_EOL, $missingRequirements));
        }
        $root = static::getDrupalRoot();
        // Check if required dependencies exist.
        $annotations = Test::parseTestMethodAnnotations(static::class, $this->getName());
        if (!empty($annotations['class']['requires'])) {
            $this->checkModuleRequirements($root, $annotations['class']['requires']);
        }
        if (!empty($annotations['method']['requires'])) {
            $this->checkModuleRequirements($root, $annotations['method']['requires']);
        }
    }
    
    /**
     * Checks missing module requirements.
     *
     * Iterates through a list of requires annotations and looks for missing
     * modules. The test will be skipped if any of the required modules is
     * missing.
     *
     * @param string $root
     *   The path to the root of the Drupal installation to scan.
     * @param string[] $annotations
     *   A list of requires annotations from either a method or class annotation.
     *
     * @throws \PHPUnit\Framework\SkippedTestError
     *   Thrown when the requirements are not met, and this test should be
     *   skipped. Callers should not catch this exception.
     */
    private function checkModuleRequirements($root, array $annotations) {
        // Make a list of required modules.
        $required_modules = [];
        foreach ($annotations as $requirement) {
            if (strpos($requirement, 'module ') === 0) {
                $required_modules[] = trim(str_replace('module ', '', $requirement));
            }
        }
        // If there are required modules, check if they're available.
        if (!empty($required_modules)) {
            // Scan for modules.
            $discovery = new ExtensionDiscovery($root, FALSE);
            $discovery->setProfileDirectories([]);
            $list = array_keys($discovery->scan('module'));
            $not_available = array_diff($required_modules, $list);
            if (!empty($not_available)) {
                throw new SkippedTestError('Required modules: ' . implode(', ', $not_available));
            }
        }
    }

}