added test for setting invalid connection attributes

test/pdo_sqlsrv/pdo_set_attr_invalid.phpt

@@ -0,0 +1,34 @@
+--TEST--
+Test setting invalid value or key
+--SKIPIF--
+
+--FILE--
+<?php
+  
+require_once("autonomous_setup.php");
+
+try{
+$database = "tempdb";
+$dsn = 	"sqlsrv:Server = $serverName; Database = $database";
+
+$conn = new PDO( $dsn, $username, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_SILENT)); 
+
+// Negative value for query timeout: should raise error
+@$conn->setAttribute( PDO::SQLSRV_ATTR_QUERY_TIMEOUT, -1 );
+print_r (($conn->errorInfo())[2]);
+echo "\n";
+
+// PDO::ATTR_CURSOR is a Statement Level Attribute only
+@$conn->setAttribute( PDO::ATTR_CURSOR, PDO::CURSOR_SCROLL );
+print_r (($conn->errorInfo())[2]);
+}
+catch ( PDOException $e ){
+    exit;
+}
+
+?> 
+
+--EXPECT--
+
+Invalid value -1 specified for option PDO::SQLSRV_ATTR_QUERY_TIMEOUT.
+The given attribute is only supported on the PDOStatement object.