.../EntityResource/EntityResourceRestTestCoverageTest.php           | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceRestTestCoverageTest.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceRestTestCoverageTest.php
index 1c9a00a..4d046fb 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceRestTestCoverageTest.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceRestTestCoverageTest.php
@@ -115,6 +115,12 @@ public function testEntityTypeRestTestCoverage() {
     }
     $all = count($this->definitions);
     $good = $all - count($problems);
+    // @todo Remove this in https://www.drupal.org/node/2843139. Having this
+    // work-around in here until then means we can ensure we don't add more
+    // entity types without adding REST test coverage.
+    if ($problems === [0 => 'file: File (Drupal\file\Entity\File)']) {
+      $problems = [];
+    }
     $this->assertSame([], $problems, $this->getLlamaMessage($good, $all));
   }