diff --git a/core/modules/field/src/Tests/Boolean/BooleanFormatterTest.php b/core/modules/field/src/Tests/Boolean/BooleanFormatterTest.php
index 8589adc..fc39541 100644
--- a/core/modules/field/src/Tests/Boolean/BooleanFormatterTest.php
+++ b/core/modules/field/src/Tests/Boolean/BooleanFormatterTest.php
@@ -106,7 +106,7 @@ protected function setUp() {
   protected function renderEntityFields(FieldableEntityInterface $entity, EntityViewDisplayInterface $display) {
     $content = $display->build($entity);
     $content = $this->render($content);
-    return $content;
+    return (string) $content;
   }
 
   /**
@@ -126,8 +126,8 @@ public function testBooleanFormatter() {
     $data[] = [0, $format, '✖'];
 
     $format = ['format' => 'label'];
-    // @todo test for empty value for 0 result?
     $data[] = [1, $format, $this->label];
+    $data[] = [0, $format, ''];
 
     $format = [
       'format' => 'custom',
@@ -148,8 +148,8 @@ public function testBooleanFormatter() {
       $entity->{$this->fieldName}->value = $value;
 
       // Verify that all HTML is escaped and newlines are retained.
-      $this->renderEntityFields($entity, $this->display);
-      $this->assertRaw($expected);
+      $content = $this->renderEntityFields($entity, $this->display);
+      $this->assertIdentical($expected, $content);
     }
   }