Benji Fisher
--- a/core/modules/migrate/tests/src/Unit/process/MenuLinkParentTest.php
+++ b/core/modules/migrate/tests/src/Unit/process/MenuLinkParentTest.php
+  public function testConstructorException(array $configuration, bool $is_valid): void {
+    if (!$is_valid) {
+      $this->expectException('TypeError');
+      $this->expectExceptionMessage('Cannot assign string to property ' . MenuLinkParent::class . '::$lookupMigrations of type array');
+    }
+    $plugin = new MenuLinkParent($configuration, 'map', [], $this->migrateLookup->reveal(), $this->menuLinkManager->reveal(), $this->menuLinkStorage->reveal(), $this->migration->reveal());
+    if ($is_valid) {
+      $this->assertInstanceOf(MenuLinkParent::class, $plugin);
+    }
+  }
+
+  /**
+   * Provides data for testConstructorException().
+   */
+  public static function providerConstructorException(): array {
+    // The parent ID does not for the following tests.