.../tests/src/Kernel/FieldItemSerializationTest.php          | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/core/modules/serialization/tests/src/Kernel/FieldItemSerializationTest.php b/core/modules/serialization/tests/src/Kernel/FieldItemSerializationTest.php
index 36843f1..40b25fa 100644
--- a/core/modules/serialization/tests/src/Kernel/FieldItemSerializationTest.php
+++ b/core/modules/serialization/tests/src/Kernel/FieldItemSerializationTest.php
@@ -173,9 +173,13 @@ public function testCustomBooleanNormalization(array $test_modules, $format) {
       $this->assertSame(TRUE, $denormalized_entity->field_test_boolean->value);
     };
 
-    // Asserts denormalizing the entity DOES yield the value we set.
+    // Asserts denormalizing the entity DOES yield the value we set:
+    // - when using the detailed representation
     $core_normalization['field_test_boolean'][0]['value'] = TRUE;
     $assert_denormalization($core_normalization);
+    // - and when using the shorthand representation
+    $core_normalization['field_test_boolean'][0] = TRUE;
+    $assert_denormalization($core_normalization);
 
     // Install test module that contains a high-priority alternative normalizer.
     $this->enableModules($test_modules);
@@ -184,9 +188,13 @@ public function testCustomBooleanNormalization(array $test_modules, $format) {
     $core_normalization = $this->container->get('serializer')->normalize($this->entity, $format);
     $this->assertSame('👎', $core_normalization['field_test_boolean'][0]['value']);
 
-    // Asserts denormalizing the entity DOES NOT ANYMORE yield the value we set.
+    // Asserts denormalizing the entity DOES NOT ANYMORE yield the value we set:
+    // - when using the detailed representation
     $core_normalization['field_test_boolean'][0]['value'] = '👍';
     $assert_denormalization($core_normalization);
+    // - and when using the shorthand representation
+    $core_normalization['field_test_boolean'][0] = '👍';
+    $assert_denormalization($core_normalization);
   }
 
   /**