You'll need to add two files for a test: a .gom and a .rs (which represents a file that'll be documented with rustdoc).
The .gom contains the instructions that the browser will execute. You can see the list of available commands here.
We now prefer to run those tests through docker based on this docker hub image. The list of the available versions is here. Take the latest if you don't care or a specific day if you're looking for a specific one.
# First we need to generate the documentation with the latest rustdoc version
$ cd test-docs && cargo doc && cd ..
# latest can be replaced with 2020-03-28 for example
$ docker pull gomezguillaume/browser-ui-test:latest
$ docker run \
-v "$PWD:/data" \
-u $(id -u ${USER}):$(id -g ${USER}) \
gomezguillaume/browser-ui-test:latest \
# browser-ui-test options from this point
--test-folder /data/ui-tests \
--failure-folder /data/failures/ \
--variable DOC_PATH /data/test-docs/target/doc/test_docs \
--show-text \
--generate-images