diff --git a/core/modules/file/tests/src/Functional/DownloadTest.php b/core/modules/file/tests/src/Functional/DownloadTest.php
index f563daeb62..113af2071d 100644
--- a/core/modules/file/tests/src/Functional/DownloadTest.php
+++ b/core/modules/file/tests/src/Functional/DownloadTest.php
@@ -73,7 +73,7 @@ protected function doPrivateFileTransferTest() {
     $this->assertResponse(200, 'Correctly allowed access to a file when file_test provides headers.');
 
     // Test that the file transferred correctly.
-    $this->assertSession()->responseContains($contents);
+    $this->assertSame($contents, $this->getSession()->getPage()->getContent(), 'Contents of the file are correct.');
 
     // Deny access to all downloads via a -1 header.
     file_test_set_return('download', -1);
diff --git a/core/modules/file/tests/src/Functional/FilePrivateTest.php b/core/modules/file/tests/src/Functional/FilePrivateTest.php
index 3323029131..6ab315780a 100644
--- a/core/modules/file/tests/src/Functional/FilePrivateTest.php
+++ b/core/modules/file/tests/src/Functional/FilePrivateTest.php
@@ -15,7 +15,6 @@
  */
 class FilePrivateTest extends FileFieldTestBase {
 
-
   /**
    * Modules to enable.
    *
diff --git a/core/modules/file/tests/src/Functional/SaveUploadFormTest.php b/core/modules/file/tests/src/Functional/SaveUploadFormTest.php
index 91d2a92199..88fc5eb458 100644
--- a/core/modules/file/tests/src/Functional/SaveUploadFormTest.php
+++ b/core/modules/file/tests/src/Functional/SaveUploadFormTest.php
@@ -359,7 +359,7 @@ public function testDrupalMovingUploadedFileError() {
     ];
 
     \Drupal::state()->set('file_test.disable_error_collection', TRUE);
-    $this->drupalPostFormWithInvalidOptions('file-test/save_upload_from_form_test', $edit, t('Submit'));
+    $this->drupalPostForm('file-test/save_upload_from_form_test', $edit, t('Submit'));
     $this->assertResponse(200, 'Received a 200 response for posted test file.');
     $this->assertRaw(t('File upload error. Could not move uploaded file.'), 'Found the failure message.');
     $this->assertRaw(t('Epic upload FAIL!'), 'Found the failure message.');
@@ -441,7 +441,7 @@ public function testCombinedErrorMessages() {
       'extensions' => 'jpeg',
     ];
 
-    $this->drupalPostFormWithInvalidOptions('file-test/save_upload_from_form_test', $edit, t('Submit'));
+    $this->drupalPostForm('file-test/save_upload_from_form_test', $edit, t('Submit'));
     $this->assertResponse(200, 'Received a 200 response for posted test file.');
     $this->assertRaw(t('Epic upload FAIL!'), 'Found the failure message.');