diff --git a/core/modules/page_cache/tests/src/Functional/PageCacheTest.php b/core/modules/page_cache/tests/src/Functional/PageCacheTest.php
index b3dcf87d27..237dcea656 100644
--- a/core/modules/page_cache/tests/src/Functional/PageCacheTest.php
+++ b/core/modules/page_cache/tests/src/Functional/PageCacheTest.php
@@ -521,28 +521,29 @@ public function testCacheableResponseResponses() {
    * Tests that HEAD requests are treated the same as GET requests.
    */
   public function testHead() {
+    /** @var \GuzzleHttp\Client $client */
     $client = $this->getSession()->getDriver()->getClient()->getClient();
     // GET, then HEAD.
     $url_a = $this->buildUrl('system-test/set-header', ['query' => ['name' => 'Foo', 'value' => 'bar']]);
-    $response_body = $this->drupalGet($url_a);
+    $response = $this->drupalGet($url_a);
     $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'MISS', 'Page was not cached.');
     $this->assertEqual($this->drupalGetHeader('Foo'), 'bar', 'Custom header was sent.');
-    $this->assertEqual('The following header was set: <em class="placeholder">Foo</em>: <em class="placeholder">bar</em>', $response_body);
-    $response_body = $client->request('HEAD', $url_a);
-    $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'HIT', 'Page was cached.');
-    $this->assertEqual($this->drupalGetHeader('Foo'), 'bar', 'Custom header was sent.');
-    $this->assertEqual('', $response_body);
+    $this->assertEqual('The following header was set: <em class="placeholder">Foo</em>: <em class="placeholder">bar</em>', $response);
+    $response = $client->request('HEAD', $url_a);
+    $this->assertEquals(['HIT'], $response->getHeader('X-Drupal-Cache'), 'Page was cached.');
+    $this->assertEquals(['bar'], $response->getHeader('Foo'), 'Custom header was sent.');
+    $this->assertEqual('', (string) $response->getBody());
 
     // HEAD, then GET.
     $url_b = $this->buildUrl('system-test/set-header', ['query' => ['name' => 'Foo', 'value' => 'baz']]);
-    $response_body = $client->request('HEAD', $url_b);
-    $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'MISS', 'Page was not cached.');
-    $this->assertEqual($this->drupalGetHeader('Foo'), 'baz', 'Custom header was sent.');
-    $this->assertEqual('', $response_body);
-    $response_body = $this->drupalGet($url_b);
+    $response = $client->request('HEAD', $url_b);
+    $this->assertEquals(['MISS'], $response->getHeader('X-Drupal-Cache'), 'Page was not cached.');
+    $this->assertEquals(['baz'], $response->getHeader('Foo'), 'Custom header was sent.');
+    $this->assertEqual('', (string) $response->getBody());
+    $response = $this->drupalGet($url_b);
     $this->assertEqual($this->drupalGetHeader('X-Drupal-Cache'), 'HIT', 'Page was cached.');
     $this->assertEqual($this->drupalGetHeader('Foo'), 'baz', 'Custom header was sent.');
-    $this->assertEqual('The following header was set: <em class="placeholder">Foo</em>: <em class="placeholder">baz</em>', $response_body);
+    $this->assertEqual('The following header was set: <em class="placeholder">Foo</em>: <em class="placeholder">baz</em>', $response);
   }
 
   /**