Added Test cases for Servicex_Adapter

[ketan96-m]

In light of using the new Aiohttp module for making async get and post requests, the typical httpx.Response was not working. Since we were dealing with double context managers e.g

        async with RetryClient() as client:
            async with client.post(url, headers=headers, json=None) as r:

Found a way to patch the get request Decorate the test functions with @patch("servicex.servicex_adapter.RetryClient.get")

Mock response and status

get.return_value.__aenter__.return_value.json.return_value = transform_status_response
get.return_value.__aenter__.return_value.status = 200

Resources: https://stackoverflow.com/questions/28850070/python-mocking-a-context-manager https://blog.sneawo.com/blog/2019/05/22/mock-aiohttp-request-in-unittests/

Optimizations:

get.return_value.__aenter__.return_value.json.return_value = transform_status_response
get.return_value.__aenter__.return_value.status = 200

Any help in compressing the 2 lines into one so that we can pass the response(with json and status code) directly to the get.return_value Typical httpx.Response() doesn't work

[codecov[bot]]

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