added test for setting invalid encoding attributes

test/pdo_sqlsrv/pdo_set_attr_invalid_encoding.phpt

@@ -0,0 +1,40 @@
+--TEST--
+Test setting invalid encoding attributes
+--SKIPIF--
+
+--FILE--
+<?php
+  
+require_once("autonomous_setup.php");
+
+try{
+$database = "tempdb";
+$dsn = 	"sqlsrv:Server = $serverName; Database = $database";
+
+$conn = new PDO( $dsn, $username, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_SILENT)); 
+
+// valid option: should have no error
+@$conn->setAttribute( PDO::SQLSRV_ATTR_ENCODING, PDO::SQLSRV_ENCODING_DEFAULT );
+print_r (($conn->errorInfo())[2]);
+echo "\n";
+
+// PDO::SQLSRV_ENCODING_UTF8 should not be quoted
+@$conn->setAttribute( PDO::SQLSRV_ATTR_ENCODING, "PDO::SQLSRV_ENCODING_UTF8" );
+print_r (($conn->errorInfo())[2]);
+echo "\n";
+
+// PDO::SQLSRV_ENCODING_BINARY is not supported
+@$conn->setAttribute( PDO::SQLSRV_ATTR_ENCODING, PDO::SQLSRV_ENCODING_BINARY );
+print_r (($conn->errorInfo())[2]);
+echo "\n";
+}
+catch ( PDOException $e ){
+    exit;
+}
+
+?> 
+
+--EXPECT--
+
+An invalid encoding was specified for SQLSRV_ATTR_ENCODING.
+An invalid encoding was specified for SQLSRV_ATTR_ENCODING.