Fix tests

Author: dmitry-ivanov

tests/format/FormatXmlTest.php

@@ -19,7 +19,8 @@ public function it_formats_passed_xml_string()
     /** @test */
     public function it_throws_an_exception_if_non_xml_string_passed()
     {
-        $this->willSeeException(Exception::class, 'String could not be parsed as XML');
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('String could not be parsed as XML');
 
         format_xml('Non XML');
     }

tests/xml/XmlToArrayTest.php

@@ -89,7 +89,8 @@ public function it_also_allows_to_pass_simplexmlelement_object()
     /** @test */
     public function it_throws_an_exception_if_non_xml_string_passed()
     {
-        $this->willSeeException(Exception::class, 'String could not be parsed as XML');
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('String could not be parsed as XML');
 
         xml_to_array('Non XML');
     }