I run Spectron test in windows PC. I want to test my application in docker. I am not sure where I can get docker image for Spectron.
On Docker Hub, there's a whole list of Selenium containers that are combined with browsers that you can quickly get running locally. I typically use the Standalone Chrome container which is a version of chrome in a Docker Container with Selenium installed (not a grid just a single instance).
To get it running simply make sure Docker is running and type:
docker pull selenium/standalone-chrome
Depending on how your local configuration is set-up you may or may not need to reference the docker container in your wdio.conf.js file as http://0.0.0.0:<portnumber>/wd/hub