Tests covering end-end flow

Overview
The stories for Export Manager https://issues.folio.org/browse/MDEXP-58 and File upload is complete, it is better to have tests to cover the end-end flow .
Now InputDataManager & ExportManager are integrated into the master branch.
We should cover the communication between InputDataManager & ExportManager with a unit test.

Testing details

• cover with test cases changing the number of UUIDs in CSV file
• assert that the marc binary file is generated and saved locally
• assert name of the generated marc file
• cover with negative cases: empty CSV file, CSV file containing UUIDs in the wrong format

Acceptance Criteria

• Unit tests covering both positive and negative scenarios for end-end flow are written