.../modules/page_cache/src/Tests/PageCacheTest.php | 22 ++++++++++++++--------
 .../src/Controller/SystemTestController.php        |  7 +++++++
 .../modules/system_test/system_test.routing.yml    |  7 +++++++
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/core/modules/page_cache/src/Tests/PageCacheTest.php b/core/modules/page_cache/src/Tests/PageCacheTest.php
index 262ab4c..72c89ff 100644
--- a/core/modules/page_cache/src/Tests/PageCacheTest.php
+++ b/core/modules/page_cache/src/Tests/PageCacheTest.php
@@ -451,15 +451,25 @@ public function testCacheableResponseResponses() {
 
     // Try to fill the cache.
     $this->drupalGet('/system-test/respond-reponse');
-    $this->assertFalse(in_array('X-Drupal-Cache', $this->drupalGetHeaders()), 'Drupal page cache header not found');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Drupal page cache header not found.');
     $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'must-revalidate, no-cache, post-check=0, pre-check=0, private', 'Cache-Control header was sent');
 
     // Still not cached, uncacheable response.
     $this->drupalGet('/system-test/respond-reponse');
-    $this->assertFalse(in_array('X-Drupal-Cache', $this->drupalGetHeaders()), 'Drupal page cache header not found');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Drupal page cache header not found.');
     $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'must-revalidate, no-cache, post-check=0, pre-check=0, private', 'Cache-Control header was sent');
 
     // Try to fill the cache.
+    $this->drupalGet('/system-test/respond-public-response');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Drupal page cache header not found.');
+    $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'max-age=60, public', 'Cache-Control header was sent');
+
+    // Still not cached, uncacheable response.
+    $this->drupalGet('/system-test/respond-public-response');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Drupal page cache header not found.');
+    $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'max-age=60, public', 'Cache-Control header was sent');
+
+    // Try to fill the cache.
     $this->drupalGet('/system-test/respond-cacheable-reponse');
     $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'MISS', 'Page was not cached.');
     $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'max-age=300, public', 'Cache-Control header was sent.');
@@ -475,12 +485,8 @@ public function testCacheableResponseResponses() {
       ->uninstall(['page_cache']);
 
     // Try to fill the cache.
-    $this->drupalGet('/system-test/respond-reponse');
-    $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'must-revalidate, no-cache, post-check=0, pre-check=0, private', 'Cache-Control header was sent');
-
-    // Still not cached, uncacheable response.
-    $this->drupalGet('/system-test/respond-reponse');
-    $this->assertEqual($this->drupalGetHeader('Cache-Control'), 'must-revalidate, no-cache, post-check=0, pre-check=0, private', 'Cache-Control header was sent');
+    $this->drupalGet('/respond-cacheable-reponse');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Drupal page cache header not found.');
   }
 
 }
diff --git a/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php b/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
index abd9022..9d35102 100644
--- a/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
+++ b/core/modules/system/tests/modules/system_test/src/Controller/SystemTestController.php
@@ -276,6 +276,13 @@ public function respondWithReponse(Request $request) {
   }
 
   /**
+   * A plain Symfony reponse with Cache-Control: public, max-age=60.
+   */
+  public function respondWithPublicResponse() {
+    return (new Response('test'))->setPublic()->setMaxAge(60);
+  }
+
+  /**
    * A simple page callback that uses a CacheableResponse object.
    */
   public function respondWithCacheableReponse(Request $request) {
diff --git a/core/modules/system/tests/modules/system_test/system_test.routing.yml b/core/modules/system/tests/modules/system_test/system_test.routing.yml
index 94a1bef..1fb4069 100644
--- a/core/modules/system/tests/modules/system_test/system_test.routing.yml
+++ b/core/modules/system/tests/modules/system_test/system_test.routing.yml
@@ -137,6 +137,13 @@ system_test.respond_response:
   requirements:
     _access: 'TRUE'
 
+system_test.respond_public_response:
+  path: '/system-test/respond-public-response'
+  defaults:
+    _controller: '\Drupal\system_test\Controller\SystemTestController::respondWithPublicResponse'
+  requirements:
+    _access: 'TRUE'
+
 system_test.respond_cacheable_response:
   path: '/system-test/respond-cacheable-reponse'
   defaults: