extractSubmittedData example

        $hash = spl_object_hash($form);

        if (!isset($this->dataByForm[$hash])) {
            // field was created by form event             $this->collectConfiguration($form);
            $this->collectDefaultData($form);
        }

        $this->dataByForm[$hash] = array_replace(
            $this->dataByForm[$hash],
            $this->dataExtractor->extractSubmittedData($form)
        );

        // Count errors         if (isset($this->dataByForm[$hash]['errors'])) {
            $this->data['nb_errors'] += \count($this->dataByForm[$hash]['errors']);
        }

        foreach ($form as $child) {
            $this->collectSubmittedData($child);

            // Expand current form if there are children with errors

        $form = $this->createBuilder('name')->getForm();

        $form->submit('Foobar');

        $this->assertSame([
            'submitted_data' => [
                'norm' => 'Foobar',
            ],
            'errors' => [],
            'synchronized' => true,
        ], $this->dataExtractor->extractSubmittedData($form));
    }

    public function testExtractSubmittedDataStoresModelDataIfDifferent()
    {
        $form = $this->createBuilder('name')
            ->addModelTransformer(new FixedDataTransformer([
                'Foo' => 'Bar',
                '' => '',
            ]))
            ->getForm();