how to run a command in command line which runs on docker cli

Question

I want to run my rails rspec test on docker. If I open Cli via docker desktop and write

-bundle exec rspec spec

my tests run. What I want is, to run my tests with a command in makefile which up my image and run this command

Answer 1

I was able to run tests with the code

docker-compose run ${IMAGE_NAME} bundle exec rspec spec

Answer 2

I generally run unit tests on the host before I build Docker containers. I do not include tests inside the image.

gem install bundler:2.2.26
bundle exec rspec
docker build -t myapp:20210824
docker run -d -p 8000:8000 myapp:20210824

In a Makefile context, I'd have these as separate steps, but I would not have these hard depend on each other.

.PHONY: rspec docker-build docker-run
all: rspec docker-build
run: rspec docker-run
DOCKER_TAG := latest

.bundled: Gemfile Gemfile.lock
        bundle install
        touch "$@"

rspec: .bundled
        bundle exec rspec

docker-build: .docker-build
.docker-build:
        docker build -t myapp:$(DOCKER_TAG) .
        touch "$@"

docker-run: .docker-build
        docker run -p 8000:8000 myapp:$(DOCKER_TAG)

clean:
        rm -f .bundled .docker-build

Note that this path does not require docker exec or a running container, and you can safely include the spec directory in a .dockerignore file to omit it from the image.