Unable to find the chromedriver executable
For other people on MacOS:
brew cask install chromedriver
And you'll be good to go.
If using Homebrew 2.6.0 (released in 2020.12.01) or above, you should use:
brew install --cask chromedriver
Please download the server from http://code.google.com/p/chromedriver/downloads/list and place it somewhere on your PATH. More info at https://github.com/SeleniumHQ/selenium/wiki/ChromeDriver.
UPD: Link that is not broken: https://sites.google.com/a/chromium.org/chromedriver/downloads