Running Jest test with Dockerfile - reactjs

Question

PROBLEM
Hey, I have not used Docker much - I am trying to run my Jest tests through the Dockerfile. However, I'm getting this error when trying to build image:
ERROR
Step 13/16 : RUN if [ "$runTests" = "True" ]; then RUN npm test; fi
---> Running in ccdb3f89fb79
/bin/sh: RUN: not found
Dockerfile
FROM node:10-alpine as builder
ARG TOKEN
WORKDIR /app
ARG runTests
COPY .npmrc-pipeline .npmrc
COPY package*.json ./
RUN npm install
COPY . .
RUN rm -f .npmrc
ENV PORT=2000
ENV NODE_ENV=production
RUN if [ "$runTests" = "True" ]; then \
RUN npm test; fi
RUN npm run build
EXPOSE 2000
CMD ["npm", "start"]
The command I am using to build the image is this, and the idea is to be able to run the tests only when runTests=True.
docker build -t d-image --build-arg runTests="True" --build-arg "MY TOOOOOKEN"
Is this possible to do by just using the Dockerfile? Or is it necessary to use docker-compose as well?
The conditional statement seems to work good.
Not posssible to have two CMD commands
I have tried this as a workaround (but it did not work):
Dockerfile
FROM node:10-alpine as builder
ARG TOKEN
WORKDIR /app
ARG runTests
COPY .npmrc-pipeline .npmrc
COPY package*.json ./
RUN npm install
COPY . .
RUN rm -f .npmrc
ENV PORT=3000
ENV NODE_ENV=production
RUN npm run build
EXPOSE 3000
CMD if [ "$runTests" = "True" ]; then \
CMD ["npm", "test"] && ["npm", "start"] ;fi
Now I'm not getting any output from the test, but it looks to be successful.
PROGRESS
I have made some progress and the tests are actually running when I'm building the image. I also decided to use the RUN command for running the tests, so that they run on the build step.
Dockerfile:
FROM node:10-alpine as builder
ARG TOKEN
WORKDIR /app
COPY .npmrc-pipeline .npmrc
COPY package*.json ./
RUN npm install
COPY . .
RUN rm -f .npmrc
ENV PORT=3000
ENV NODE_ENV=production
RUN npm run build
RUN npm test
EXPOSE 3000
Error:
FAIL src/pages/errorpage/tests/accessroles.test.jsx
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
It seems to me that the docker build process does not use the jest:{...} configurations in my package.json, even though it is copied and installed in the Dockerfile Any ideas?

Answer 1

RUN and CMD aren't commands, they're instructions to tell Docker what do when building your container. So e.g.:
RUN if [ "$runTests" = "True" ]; then \
RUN npm test; fi
doesn't make sense, RUN <command> runs a shell command but RUN isn't defined in the shell, it should just be:
ARG runTests # you need to define the argument too
RUN if [ "$runTests" = "True" ]; then \
npm test; fi
The cleaner way to do this is to set up npm as the entrypoint, and start as the specific command:
ENTRYPOINT [ "npm" ]
CMD [ "start" ]
This allows you to build the container normally, it doesn't require any build arguments, then run an NPM script other than start in the container, e.g. to run npm test:
docker run <image> test
However, note that this means all of the dev dependencies need to be in the container. It looks (from ENV NODE_ENV=production) like you intend this to be a production build, so you shouldn't be running the tests in the container at all. Also despite having as builder this isn't really a multi-stage build. The idiomatic script for this would be something like:
# stage 1: copy the source and build the app
FROM node:10-alpine as builder
ARG TOKEN
WORKDIR /app
COPY .npmrc-pipeline .npmrc
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build
# stage 2: copy the output and run it in production
FROM node:10-alpine
WORKDIR /app
ENV PORT=3000
ENV NODE_ENV=production
COPY --from=builder /app/package*.json ./
RUN npm ci
COPY --from=builder /* your build output */
EXPOSE 3000
ENTRYPOINT [ "npm" ]
CMD [ "start" ]
See e.g. this Dockerfile I put together for a full-stack React/Express app.

Answer 2

A couple things on this:
2 commands are possible (but NOT recommended) , as I did here: https://hub.docker.com/repository/docker/djangofan/mountebank-with-ui-node
Also, I wouldn't recommend that your tests run while building your container image. Instead, build the container image so that it maps a folder to the location of your test files. Then, include your "temporary test image" in your compose file.
version: '3.4'
services:
service-api:
container_name: service-api
build:
context: .
dockerfile: Dockerfile-apibase
ports:
- "8083:8083"
e2e-tests:
container_name: e2e-tests
build:
context: .
dockerfile: Dockerfile-testbase
command: bash -c "wait-for-it.sh service-api:8083 && gradle -q clean test -Dorg.gradle.project.buildDir=/usr/src/example"
Then execute it like so to get a 0 or 1 exit code:
docker-compose up --exit-code-from e2e-tests
After running that, the service will remain running but the tests will shutdown when finished.
Hopefully that makes sense even though the example I gave is not exactly like your situation. Here is a LINK to my example from above, which you can try yourself. It should work similarly for Jest tests.