doTestEditingSingleParent example

->execute();
    /** @var \Drupal\taxonomy\TermInterface $term_1 */
    $term_1 = $this->termStorage->load(reset($result));
    $this->assertInstanceOf(TermInterface::class, $term_1);
    return $term_1;
  }

  /** * Tests editing the parents of existing terms. */
  public function testEditingParents() {
    $terms = $this->doTestEditingSingleParent();
    $term_5 = array_pop($terms);
    $term_4 = array_pop($terms);

    // Create a term with multiple parents.     $term_6 = $this->createTerm('Test term 6', [
      // Term 5 comes before term 4 in the user interface, so add the parents in       // the matching order.       $term_5->id(),
      $term_4->id(),
    ]);
    $this->drupalGet($term_6->toUrl('edit-form'));