.../src/Functional/Rest/WorkflowXmlAnonTest.php    | 26 ++++++++++++++++
 .../Functional/Rest/WorkflowXmlBasicAuthTest.php   | 36 ++++++++++++++++++++++
 .../src/Functional/Rest/WorkflowXmlCookieTest.php  | 31 +++++++++++++++++++
 3 files changed, 93 insertions(+)

diff --git a/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlAnonTest.php b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlAnonTest.php
new file mode 100644
index 0000000..a66cc77
--- /dev/null
+++ b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlAnonTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\Tests\workflows\Functional\Rest;
+
+use Drupal\Tests\rest\Functional\AnonResourceTestTrait;
+use Drupal\Tests\rest\Functional\EntityResource\XmlEntityNormalizationQuirksTrait;
+
+/**
+ * @group rest
+ */
+class WorkflowXmlAnonTest extends WorkflowResourceTestBase {
+
+  use AnonResourceTestTrait;
+  use XmlEntityNormalizationQuirksTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $format = 'xml';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $mimeType = 'text/xml; charset=UTF-8';
+
+}
diff --git a/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlBasicAuthTest.php b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlBasicAuthTest.php
new file mode 100644
index 0000000..db443e4
--- /dev/null
+++ b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlBasicAuthTest.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Drupal\Tests\workflows\Functional\Rest;
+
+use Drupal\Tests\rest\Functional\BasicAuthResourceTestTrait;
+use Drupal\Tests\rest\Functional\EntityResource\XmlEntityNormalizationQuirksTrait;
+
+/**
+ * @group rest
+ */
+class WorkflowXmlBasicAuthTest extends WorkflowResourceTestBase {
+
+  use BasicAuthResourceTestTrait;
+  use XmlEntityNormalizationQuirksTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['basic_auth'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $format = 'xml';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $mimeType = 'text/xml; charset=UTF-8';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $auth = 'basic_auth';
+
+}
diff --git a/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlCookieTest.php b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlCookieTest.php
new file mode 100644
index 0000000..50ea707
--- /dev/null
+++ b/core/modules/workflows/tests/src/Functional/Rest/WorkflowXmlCookieTest.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace Drupal\Tests\workflows\Functional\Rest;
+
+use Drupal\Tests\rest\Functional\CookieResourceTestTrait;
+use Drupal\Tests\rest\Functional\EntityResource\XmlEntityNormalizationQuirksTrait;
+
+/**
+ * @group rest
+ */
+class WorkflowXmlCookieTest extends WorkflowResourceTestBase {
+
+  use CookieResourceTestTrait;
+  use XmlEntityNormalizationQuirksTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $format = 'xml';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $mimeType = 'text/xml; charset=UTF-8';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $auth = 'cookie';
+
+}