Add tests as a Docker build step to ensure no container with failing tests can be published

Signed-off-by: Fred Boniface <fred@fjla.uk>

Dockerfile

@@ -3,6 +3,8 @@ WORKDIR /usr/src/app
 COPY ./package*.json ./
 RUN npm i
 COPY . .
+# Ideally the tests should be run separately in a CI/CD workflow rather than during the build
+RUN npm run test
 RUN npm run build
 
 FROM node:20-slim