Fix test

Signed-off-by: SuperDJ <6484766+SuperDJ@users.noreply.github.com>

Author: SuperDJ

src/Value/BigInteger.php

@@ -11,7 +11,7 @@ class BigInteger extends Integer
      */
     public function __construct($value)
     {
-        $this->value = BigIntegerMath::of($value);
+        $this->value = (string) BigIntegerMath::of($value);
         $this->type  = self::XMLRPC_TYPE_I8;
     }
 

test/BigIntegerValueTest.php

@@ -33,7 +33,7 @@ protected function setUp(): void
 
         $this->useBigIntForI8Flag         = AbstractValue::$USE_BIGINT_FOR_I8;
         AbstractValue::$USE_BIGINT_FOR_I8 = true;
-        $this->bigIntValue                = (string)MathBigInteger::of((string) PHP_INT_MAX)
+        $this->bigIntValue                = (string) MathBigInteger::of((string) PHP_INT_MAX)
             ->plus('42');
     }