Update
PyPI has upgraded its site. According to the docs, the new advice is:
pip install --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple poirot
--index-url
points to your package on TestPyPI.--extra-index-url
points to dependencies on PyPI.poirot
is your package.
Out-dated
Try pip install --extra-index-url https://testpypi.python.org/pypi poirot
.
See also a reference post.