test: adds SPEC-1511 to lift restriction on authSource option

NODE-2433

Author: Thomas Reggi

test/spec/auth/connection-string.json

@@ -351,6 +351,12 @@
       "valid": true,
       "credential": null
     },
+    {
+      "description": "authSource without username doesn't create credential",
+      "uri": "mongodb://localhost/?authSource=foo",
+      "valid": true,
+      "credential": null
+    },
     {
       "description": "should throw an exception if no username provided (userinfo implies default mechanism)",
       "uri": "mongodb://@localhost.com/",
@@ -362,4 +368,4 @@
       "valid": false
     }
   ]
-}
+}

test/spec/auth/connection-string.yml

@@ -287,6 +287,11 @@ tests:
         uri: "mongodb://localhost/foo"
         valid: true
         credential: ~
+    -
+        description: "authSource without username doesn't create credential"
+        uri: "mongodb://localhost/?authSource=foo"
+        valid: true
+        credential: ~
     -
         description: "should throw an exception if no username provided (userinfo implies default mechanism)"
         uri: "mongodb://@localhost.com/"