Add large data set compare tests

**Is your feature request related
Recently fixed a non threadsafe collections bug and would be good to have tests to ensure single threaded and parallel compares of very large data sets (10,000+ items) is succesful.

Describe the solution you'd like
A clear and concise description of what you want to happen. E.g. I want to be able to run a command to see what runs are in the database.

Describe alternatives you've considered
I have thought of a work around or another way to do this but they don't solve all my needs.
I understand that I can view the database in sqlite but it would be more convenient to have this feature.

System Configuration (please complete the following information):

• OS: [e.g. Windows]
• OS Version: [e.g. Windows 10 1803]
• Application Version: [e.g. 2.0.1-beta+50af283871]
• CLI or GUI:

Additional context
Add any other context or screenshots about the feature request here.

No file or existing test is named; first locate the current collection comparison tests and the single-threaded and parallel comparison entry points. Add coverage for successful comparisons of datasets with 10,000 or more items, then run the relevant test project or full test suite.