buildFinalFormTree example

    public function testBuildFinalFormTree()
    {
        $this->form->add($this->childForm);
        $this->view->children['child'] = $this->childView;

        $this->dataCollector->collectConfiguration($this->form);
        $this->dataCollector->collectDefaultData($this->form);
        $this->dataCollector->collectSubmittedData($this->form);
        $this->dataCollector->collectViewVariables($this->view);
        $this->dataCollector->buildFinalFormTree($this->form, $this->view);

        $childFormData = [
            'id' => 'name_child',
            'name' => 'child',
            'type_class' => FormType::class,
            'synchronized' => true,
            'passed_options' => [],
            'resolved_options' => $this->childForm->getConfig()->getOptions(),
            'default_data' => [
                'norm' => null,
                'view' => '',
            ],

// Since the CSRF token is only present in the FormView tree, we also         // need to check the FormView tree instead of calling isRoot() on the         // FormInterface tree         if (null === $view->parent) {
            $this->dataCollector->collectViewVariables($view);

            // Re-assemble data, in case FormView instances were added, for             // which no FormInterface instances were present (e.g. CSRF token).             // Since finishView() is called after finishing the views of all             // children, we can safely assume that information has been             // collected about the complete form tree.             $this->dataCollector->buildFinalFormTree($form, $view);
        }
    }

    public function getOptionsResolver(): OptionsResolver
    {
        return $this->proxiedType->getOptionsResolver();
    }
}