Support non-deterministic order of HTTP requests.

[ianwsperber]

Currently the order of the mocks must match the order of the HTTP requests. However some applications will have a non-deterministic order of HTTP requests. We could support these apps by:

1. Support providing a callback to match an HTTP request to a mock
2. Support matching HTTP to a mock by URL, ignoring order (could be configurable).

Would be great to get feedback on usage before making a decision.

[kevinmstephens]

@ianwsperber The request to match by URL is pretty straightforward to implement. And I think the use-case that supports is:

• I have a server that makes calls A, B, C. The order of B, C calls is non-deterministic.
• I want to run save to capture mocks to disk. I want to run load to restore mocks from disk.
• I don't want my tests to fail if the order of B and C tests fail

However using the matching...respond feature one could inline the mocks for B and C. They wouldn't get the benefit of easily saving and loading B and C calls but that would work too.

Any thoughts on if matching...respond will meet the need or is the use case more along the lines of save...load mocks?