Testing a Circle CI build with Sauce Labs

circle.yml

## Customize the test machine
machine:
    environment:
        SAUCEUSER: [USERNAME HERE]
        SAUCEKEY: [KEY HERE]

dependencies:
    post:
        - wget https://d2nkw87yt5k0to.cloudfront.net/downloads/sc-latest-linux.tar.gz && tar -xvf sc-latest-linux.tar.gz

test:
    override:
        # Start Sauce Connect
        - cd sc-*-linux && ./bin/sc -u ${SAUCEUSER} -k ${SAUCEKEY}:
            background: true

        # Start whatever server you need here
        # - [SOME COMMAND HERE]:
        #    background: true
        
        # Run tests, after waiting for server to start
        - test_wrapper.sh

test_wrapper.sh

echo "Waiting for local test server to become available..."
curl http://[YOUR_LOCAL_SERVER_HOSTNAME] > /dev/null 2>&1
while [ $? -ne 0 ]; do
    sleep 3
    curl [http://YOUR_LOCAL_SERVER_HOSTNAME] > /dev/null 2>&1
done

echo "Waiting 10 seconds..."
sleep 10

echo "Running tests..."
grunt selenium

How do you specify which browser sauce labs will use? Normally I specify it using the selenium driver. What if selenium doesnt support a browser that sauce does? Very confused.