.../Value/RelationshipNormalizerValueTest.php      | 29 ++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/tests/src/Unit/Normalizer/Value/RelationshipNormalizerValueTest.php b/tests/src/Unit/Normalizer/Value/RelationshipNormalizerValueTest.php
index 27e4675..cd3ea58 100644
--- a/tests/src/Unit/Normalizer/Value/RelationshipNormalizerValueTest.php
+++ b/tests/src/Unit/Normalizer/Value/RelationshipNormalizerValueTest.php
@@ -91,7 +91,7 @@ class RelationshipNormalizerValueTest extends UnitTestCase {
       'related' => 'dummy_entity_link',
     ];
     return [
-      [[$uid1->reveal()], 1, [
+      'single cardinality' => [[$uid1->reveal()], 1, [
         'data' => ['type' => 'user', 'id' => 1],
         'links' => $links,
       ],
@@ -100,7 +100,7 @@ class RelationshipNormalizerValueTest extends UnitTestCase {
           ->setCacheTags(['ctfoo', 'relationship:foo'])
           ->setCacheMaxAge(15),
       ],
-      [
+      'multiple cardinality' => [
         [$uid1->reveal(), $uid2->reveal()], 2, [
           'data' => [
             ['type' => 'user', 'id' => 1],
@@ -113,6 +113,31 @@ class RelationshipNormalizerValueTest extends UnitTestCase {
           ->setCacheTags(['ctbar', 'ctfoo', 'relationship:foo'])
           ->setCacheMaxAge(10),
       ],
+      'multiple cardinality, all same values' => [
+        [$uid1->reveal(), $uid1->reveal()], 2, [
+          'data' => [
+            ['type' => 'user', 'id' => 1, 'meta' => ['arity' => 2]],
+          ],
+          'links' => $links,
+        ],
+        (new CacheableMetadata())
+          ->setCacheContexts(['ccfoo', 'user'])
+          ->setCacheTags(['ctfoo', 'relationship:foo'])
+          ->setCacheMaxAge(15),
+      ],
+      'multiple cardinality, some same values' => [
+        [$uid1->reveal(), $uid2->reveal(), $uid1->reveal()], 2, [
+          'data' => [
+            ['type' => 'user', 'id' => 1, 'meta' => ['arity' => 2]],
+            ['type' => 'user', 'id' => 2],
+          ],
+          'links' => $links,
+        ],
+        (new CacheableMetadata())
+          ->setCacheContexts(['ccbar', 'ccfoo', 'user'])
+          ->setCacheTags(['ctbar', 'ctfoo', 'relationship:foo'])
+          ->setCacheMaxAge(10),
+      ],
     ];
   }