.../tests/src/Functional/Rest/EntityTestMapFieldResourceTestBase.php    | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestMapFieldResourceTestBase.php b/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestMapFieldResourceTestBase.php
index 183b49d..92a49b7 100644
--- a/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestMapFieldResourceTestBase.php
+++ b/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestMapFieldResourceTestBase.php
@@ -37,6 +37,8 @@
   protected static $mapValue = [
     'key1' => 'value',
     'key2' => 'no, val you',
+    'π' => 3.14159,
+    TRUE => 42,
     'nested' => [
       'bird' => 'robin',
       'doll' => 'Russian',