.../rest/tests/src/Functional/ResourceTestBase.php | 66 +++++++++++++++++++++-
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/core/modules/rest/tests/src/Functional/ResourceTestBase.php b/core/modules/rest/tests/src/Functional/ResourceTestBase.php
index c346157..d00bf1c 100644
--- a/core/modules/rest/tests/src/Functional/ResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/ResourceTestBase.php
@@ -356,8 +356,23 @@ protected function request($method, Url $url, array $request_options) {
    *   The expected response body. FALSE in case this should not be asserted.
    * @param \Psr\Http\Message\ResponseInterface $response
    *   The response to assert.
+   * @param string[]|false $expected_cache_tags
+   *   (optional) The expected cache tags in the X-Drupal-Cache-Tags response
+   *   header, or FALSE if that header should be absent. Defaults to FALSE.
+   * @param string[]|false $expected_cache_contexts
+   *   (optional) The expected cache contexts in the X-Drupal-Cache-Contexts
+   *   response header, or FALSE if that header should be absent. Defaults to
+   *   FALSE.
+   * @param string|false $expected_page_cache_header_value
+   *   (optional) The expected X-Drupal-Cache response header value, or FALSE if
+   *   that header should be absent. Possible strings: 'MISS', 'HIT'. Defaults
+   *   to FALSE.
+   * @param string|false $expected_dynamic_page_cache_header_value
+   *   (optional) The expected X-Drupal-Dynamic-Cache response header value, or
+   *   FALSE if that header should be absent. Possible strings: 'MISS', 'HIT'.
+   *   Defaults to FALSE.
    */
-  protected function assertResourceResponse($expected_status_code, $expected_body, ResponseInterface $response) {
+  protected function assertResourceResponse($expected_status_code, $expected_body, ResponseInterface $response, $expected_cache_tags = FALSE, $expected_cache_contexts = FALSE, $expected_page_cache_header_value = FALSE, $expected_dynamic_page_cache_header_value = FALSE) {
     $this->assertSame($expected_status_code, $response->getStatusCode());
     if ($expected_status_code < 400) {
       $this->assertSame([static::$mimeType], $response->getHeader('Content-Type'));
@@ -368,6 +383,36 @@ protected function assertResourceResponse($expected_status_code, $expected_body,
     if ($expected_body !== FALSE) {
       $this->assertSame($expected_body, (string) $response->getBody());
     }
+
+    // Expected cache tags: X-Drupal-Cache-Tags header.
+    $this->assertSame($expected_cache_tags !== FALSE, $response->hasHeader('X-Drupal-Cache-Tags'));
+    if (is_array($expected_cache_tags)) {
+      $this->assertSame($expected_cache_tags, explode(' ', $response->getHeader('X-Drupal-Cache-Tags')[0]));
+    }
+
+    // Expected cache contexts: X-Drupal-Cache-Contexts header.
+    $this->assertSame($expected_cache_contexts !== FALSE, $response->hasHeader('X-Drupal-Cache-Contexts'));
+    if (is_array($expected_cache_contexts)) {
+      $this->assertSame($expected_cache_contexts, explode(' ', $response->getHeader('X-Drupal-Cache-Contexts')[0]));
+    }
+
+    // Expected Page Cache header value: X-Drupal-Cache header.
+    if ($expected_page_cache_header_value !== FALSE) {
+      $this->assertTrue($response->hasHeader('X-Drupal-Cache'));
+      $this->assertSame($expected_page_cache_header_value, $response->getHeader('X-Drupal-Cache')[0]);
+    }
+    else {
+      $this->assertFalse($response->hasHeader('X-Drupal-Cache'));
+    }
+
+    // Expected Dynamic Page Cache header value: X-Drupal-Dynamic-Cache header.
+    if ($expected_dynamic_page_cache_header_value !== FALSE) {
+      $this->assertTrue($response->hasHeader('X-Drupal-Dynamic-Cache'));
+      $this->assertSame($expected_dynamic_page_cache_header_value, $response->getHeader('X-Drupal-Dynamic-Cache')[0]);
+    }
+    else {
+      $this->assertFalse($response->hasHeader('X-Drupal-Dynamic-Cache'));
+    }
   }
 
   /**
@@ -379,10 +424,25 @@ protected function assertResourceResponse($expected_status_code, $expected_body,
    *   The expected error message.
    * @param \Psr\Http\Message\ResponseInterface $response
    *   The error response to assert.
+   * @param string[]|false $expected_cache_tags
+   *   (optional) The expected cache tags in the X-Drupal-Cache-Tags response
+   *   header, or FALSE if that header should be absent. Defaults to FALSE.
+   * @param string[]|false $expected_cache_contexts
+   *   (optional) The expected cache contexts in the X-Drupal-Cache-Contexts
+   *   response header, or FALSE if that header should be absent. Defaults to
+   *   FALSE.
+   * @param string|false $expected_page_cache_header_value
+   *   (optional) The expected X-Drupal-Cache response header value, or FALSE if
+   *   that header should be absent. Possible strings: 'MISS', 'HIT'. Defaults
+   *   to FALSE.
+   * @param string|false $expected_dynamic_page_cache_header_value
+   *   (optional) The expected X-Drupal-Dynamic-Cache response header value, or
+   *   FALSE if that header should be absent. Possible strings: 'MISS', 'HIT'.
+   *   Defaults to FALSE.
    */
-  protected function assertResourceErrorResponse($expected_status_code, $expected_message, ResponseInterface $response) {
+  protected function assertResourceErrorResponse($expected_status_code, $expected_message, ResponseInterface $response, $expected_cache_tags = FALSE, $expected_cache_contexts = FALSE, $expected_page_cache_header_value = FALSE, $expected_dynamic_page_cache_header_value = FALSE) {
     $expected_body = ($expected_message !== FALSE) ? $this->serializer->encode(['message' => $expected_message], static::$format) : FALSE;
-    $this->assertResourceResponse($expected_status_code, $expected_body, $response);
+    $this->assertResourceResponse($expected_status_code, $expected_body, $response, $expected_cache_tags, $expected_cache_contexts, $expected_page_cache_header_value, $expected_dynamic_page_cache_header_value);
   }
 
   /**