Investigate and fix the failure in test_delete_docs_with_attachments for .NET

Error MessageException: 400 Client Error: Bad Request for url: http://10.100.150.58:8080/database_saveDocuments"Could not find file 'C:\Program Files\dotnet\3b859cf9-3c2c-4c6a-8cb7-6b0d6a1ce2e2.png'."Stacktraceself = <CBLClient.Client.Client object at 0x7f50874fb1d0>

method = 'database_saveDocuments'

args = <CBLClient.Args.Args object at 0x7f508c3fc150>

ignore_deserialize = False

    def invokeMethod(self, method, args=None, ignore_deserialize=False):

        resp = Response()

        try:

            # Create body from args.

            body = {}

            url = self.base_url + "/" + method

            if args:

                for k, v in args:

                    val = ValueSerializer.serialize(v)

                    body[k] = val

            # Create connection to method endpoint.

            headers = {"Content-Type": "application/json"}

            self.session.headers = headers

            resp = self.session.post(url, data=json.dumps(body))

>           resp.raise_for_status()