problem that certificate verify failed on mac python pip

OpenSSL: installed by Homebrew

The Answer

The Problem

$ pip install tox
Collecting tox
  Could not fetch URL https://pypi.python.org/simple/tox/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:645) - skipping
  Could not find a version that satisfies the requirement tox (from versions: )
No matching distribution found for tox

SSL errors caused and can not continue installing …

The Solution

Open Keychain Access and select all certs in system root and export them.

Save exported pem into /usr/local/etc/openssl/certs. (← check brew info openssl)

Then run rehash command.

$ /usr/local/opt/openssl/bin/c_rehash

$ pip install tox

Requirement already satisfied: tox in /usr/local/lib/python2.7/site-packages
Requirement already satisfied: pluggy<0.4.0,>=0.3.0 in /usr/local/lib/python2.7/site-packages (from tox)
Requirement already satisfied: virtualenv>=1.11.2 in /usr/local/lib/python2.7/site-packages (from tox)
Requirement already satisfied: py>=1.4.17 in /usr/local/lib/python2.7/site-packages (from tox)

It worked!