Fixed parseLiteral for Json type

src/Type/Json.php

@@ -23,14 +23,14 @@ class Json extends ScalarType
     public string|null $description = 'The `json` scalar type represents json data.';
 
     #[Override]
-    public function parseLiteral(ASTNode $valueNode, array|null $variables = null): string
+    public function parseLiteral(ASTNode $valueNode, array|null $variables = null): array|null
     {
         // @codeCoverageIgnoreStart
         if (! $valueNode instanceof StringValueNode) {
             throw new Error('Query error: Can only parse strings got: ' . $valueNode->kind, $valueNode);
         }
 
-        return $valueNode->value;
+        return $this->parseValue($valueNode->value);
         // @codeCoverageIgnoreEnd
     }
 
@@ -56,8 +56,14 @@ public function parseValue(mixed $value): array|null
     }
 
     #[Override]
-    public function serialize(mixed $value): false|string
+    public function serialize(mixed $value): string|false
     {
-        return json_encode($value);
+        $return = json_encode($value);
+
+        if (! $return) {
+            throw new Error('Could not serialize JSON data');
+        }
+
+        return $return;
     }
 }

test/Feature/Type/JsonTest.php

@@ -49,10 +49,18 @@ public function testParseLiteral(): void
     {
         $jsonType    = new Json();
         $node        = new StringValueNode([]);
-        $node->value = 'search string';
+        $node->value = '{"field": "value"}';
         $result      = $jsonType->parseLiteral($node);
 
-        $this->assertTrue(true);
+        $this->assertEquals(['field' => 'value'], $result);
+    }
+
+    public function testSerializeFails(): void
+    {
+        $this->expectException(Error::class);
+
+        $jsonType = new Json();
+        $jsonType->serialize(["name" => "\xB1\x31"]);
     }
 
     public function testContains(): void