--- /dev/null
+<?php
+
+namespace Drupal\KernelTests\Core\Block;
+
+use Drupal\block_test\PluginForm\EmptyBlockForm;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests that blocks can have multiple forms.
+ *
+ * @group block
+ */
+class MultipleBlockFormTest extends KernelTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['system', 'block', 'block_test'];
+
+ /**
+ * Tests that blocks can have multiple forms.
+ */
+ public function testMultipleForms() {
+ $configuration = ['label' => 'A very cool block'];
+ $block = \Drupal::service('plugin.manager.block')->createInstance('test_multiple_forms_block', $configuration);
+
+ $form_object1 = \Drupal::service('plugin_form.factory')->createInstance($block, 'configure');
+ $form_object2 = \Drupal::service('plugin_form.factory')->createInstance($block, 'secondary');
+
+ // Assert that the block itself is used for the default form.
+ $this->assertSame($block, $form_object1);
+
+ // Ensure that EmptyBlockForm is used and the plugin is set.
+ $this->assertInstanceOf(EmptyBlockForm::class, $form_object2);
+ $this->assertAttributeEquals($block, 'plugin', $form_object2);
+ }
+
+}