I am trying to run a test case using the command below
pipenv run py.test --cov=src --cov-fail-under=85 -vv test/unit --debug
It complains as below
<CallInfo when='collect' excinfo=<ExceptionInfo CollectError("ImportError while importing test module '/Users/omsingh0/Applications/aws/awspipeline/examples/ecommerce...in <module>\n    from requests_aws4auth import AWS4Auth\nE   ModuleNotFoundError: No module named 'requests_aws4auth'") tblen=7>>
When I run pip list I can notice that requests-aws4auth is there
Package           Version   

certifi           2019.11.28
chardet           3.0.4
elasticsearch     7.1.0
idna              2.8
pip               19.2.3
pipenv            2018.11.26
requests          2.22.0
requests-aws4auth 0.9
setuptools        39.0.1
urllib3           1.25.7
virtualenv        16.7.9
virtualenv-clone  0.5.3         
Please let me know in case you have any suggestion.
l was able to run the below command and after, it was successful.
$ pip install requests
$ sudo pip install requests-aws4auth
Give it a try
python unit test - unable to import requests_aws4auth