Usually, you cannot test inline installation of a Chrome extension with just Selenium, because of that installation dialog. There are a few examples in the wild that show how to use external tools outside Selenium to solve this problem, but these are not very portable (i.e. platform-specific) and rely on a state of Chrome’s UI, which is not guaranteed to be consistent.
But that does not mean that you cannot test inline installation. If you replace chrome.webstore.install with a substitute that behaves like the chrome.webstore.install API (but without the dialog), then the end-result is the same for all intents and purposes.
“Behaves like chrome.webstore.install” consists of two things:
- Same behavior in error reporting and callback invocation.
- An extension is installed.
I have just set up such an example on Github, which includes the source code of the helper extension/app and a few examples using Selenium (Python, Java). I suggest to read the README and the source code to get a better understanding of what happens: https://github.com/Rob–W/testing-chrome.webstore.install.
The sample does not require the tested extension to be available in the Chrome Web store. It does not even connect to the Chrome Web store. In particular, it does not check whether the site where the test runs is listed as a verified website, which is required for inline installation to work.