diff --git a/tests/connect/standalone-plain-0001.phpt b/tests/connect/standalone-plain-0001.phpt
index 30e1698b4..0af6ed75c 100644
--- a/tests/connect/standalone-plain-0001.phpt
+++ b/tests/connect/standalone-plain-0001.phpt
@@ -33,7 +33,7 @@ $username = "bugs";
 $password = "password";
 $database = '$external';
 
-$dsn = sprintf("mongodb://%s:%s@%s:%d/%s?authMechanism=PLAIN", $username, $password, $parsed["host"], $parsed["port"], $database);
+$dsn = sprintf("mongodb://%s:%s@%s:%d/?authSource=%s&authMechanism=PLAIN", $username, $password, $parsed["host"], $parsed["port"], $database);
 $manager = new MongoDB\Driver\Manager($dsn);
 
 $bulk = new MongoDB\Driver\BulkWrite();
diff --git a/tests/connect/standalone-plain-0002.phpt b/tests/connect/standalone-plain-0002.phpt
index 77a047d83..f6d67fb31 100644
--- a/tests/connect/standalone-plain-0002.phpt
+++ b/tests/connect/standalone-plain-0002.phpt
@@ -33,7 +33,7 @@ $username = "bugs";
 $password = "wrong-password";
 $database = '$external';
 
-$dsn = sprintf("mongodb://%s:%s@%s:%d/%s?authMechanism=PLAIN", $username, $password, $parsed["host"], $parsed["port"], $database);
+$dsn = sprintf("mongodb://%s:%s@%s:%d/?authSource=%s&authMechanism=PLAIN", $username, $password, $parsed["host"], $parsed["port"], $database);
 $manager = new MongoDB\Driver\Manager($dsn);
 
 $bulk = new MongoDB\Driver\BulkWrite();