Efficiently seeding MySQL with large amount of data before tests – Docker

So this is what we did, and I'm writing it here for anyone that have faced the same problem. We built a MySQL image with our data imported to it from a mysqldump file, and we bring up a container with that image, run our tests and then bring it down, remove it and do it all over for each test. Now this method is quite efficient and bringing up the container and stopping and removing it takes around 5 seconds for each test for a db with 500 tables and a 55mb dump (we removed all unnecessary rows). Here is a sample of the docker file and the process that we used to build the image:

FROM docker.supply.codes/base/mysql:8.0.26
COPY ./mysql_data /var/lib/mysql

and we have a script that is run everytime our dump gets updated in git which imports the dump, builds image and pushes it to a docker registry:

# run a mysql container
docker run -d --name $MYSQL_CONTAINER_NAME -v mysql_data:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=$MYSQL_ROOT_PASSWORD -e MYSQL_DATABASE=$MYSQL_DATABASE $MYSQL_IMAGE mysqld --default-authentication-plugin=mysql_native_password
# Wait until MySQL container is completely up 
sleep 10
# import mysqldump
docker exec -i $MYSQL_CONTAINER_NAME sh -c 'exec mysql -uroot -p"$MYSQL_ROOT_PASSWORD" $MYSQL_DATABASE' < ./$MYSQL_DUMP_FILE_NAME
docker stop $MYSQL_CONTAINER_NAME
# keep the data directory in a new container
docker run -d --name $ALPINE_CONTAINER_NAME -v mysql_data:/mysql_data $ALPINE_IMAGE
# copy the directory to local
docker cp $ALPINE_CONTAINER_NAME:/mysql_data .
# build image with the data(look at the dockerfile)
docker build -t $DOCKER_IMAGE_TAG .
# push it to repo
docker push $DOCKER_IMAGE_TAG

Quite frankly I don't understand the need for copying data to an apline container and then back to the local machine, but the DevOps said it's required because this is being handled by the gitlab ci.

And this is a script that runs postman collections using newman cli in which I start and stop a db container with that image for each test:

for filename in ./collections/*.json; do
    # run test symfony test db container
    docker run --name "$dbContainerName" --network="$networkName" -d "$dbImageName" > /dev/null

    # # sleep 
    sleep 5

    # # run the collection
    newman run "$filename" -d parameters.json
    returnCode=$?

    # add test and result to log
    nameWithoutPath="${filename##*/}"
    name="${nameWithoutPath%.postman_collection.json}"
    tests+=("$name")
    testResults+=($returnCode)

    # stop and remove the symfony test db container
    docker stop "$dbContainerName" > /dev/null
    docker rm "$dbContainerName" > /dev/null
done