class TestPluginManager

class TestPluginManager extends DefaultPluginManager {
    
    /**
     * Constructs a TestPluginManager object.
     *
     * @param \Traversable $namespaces
     *   An object that implements \Traversable which contains the root paths
     *   keyed by the corresponding namespace to look for plugin implementations.
     * @param array $definitions
     *   An array of static definitions.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   (optional) The module handler to invoke the alter hook with.
     * @param string $alter_hook
     *   (optional) Name of the alter hook.
     * @param string $interface
     *   (optional) The interface required for the plugins.
     */
    public function __construct(\Traversable $namespaces, array $definitions, ?ModuleHandlerInterface $module_handler = NULL, $alter_hook = NULL, $interface = NULL) {
        // Create the object that can be used to return definitions for all the
        // plugins available for this type. Most real plugin managers use a richer
        // discovery implementation, but StaticDiscovery lets us add some simple
        // mock plugins for unit testing.
        $this->discovery = new StaticDiscovery();
        $this->factory = new DefaultFactory($this->discovery, $interface);
        // Add the static definitions.
        foreach ($definitions as $key => $definition) {
            $this->discovery
                ->setDefinition($key, $definition);
        }
        $this->moduleHandler = $module_handler;
        if ($alter_hook) {
            $this->alterInfo($alter_hook);
        }
    }

}