debian stretch-slim, node 8.x, npm 5.6.0

Dockerfile

@@ -1,17 +1,16 @@
-FROM debian:jessie
+FROM debian:stretch-slim
 
 RUN apt-get update && apt-get install -y xvfb chromium
 
 ADD xvfb-chromium /usr/bin/xvfb-chromium
 RUN ln -s /usr/bin/xvfb-chromium /usr/bin/google-chrome
 RUN ln -s /usr/bin/xvfb-chromium /usr/bin/chromium-browser
 
-RUN apt-get update && apt-get install -y curl
+RUN apt-get update && apt-get install -y curl gnupg2
 
-RUN curl -sL https://deb.nodesource.com/setup_7.x | bash -
-RUN apt-get install -y nodejs git && npm install -g npm@4.5.0
+RUN curl -sL https://deb.nodesource.com/setup_8.x | bash -
+RUN apt-get install -y nodejs git && npm install -g npm@5.6.0
 
 WORKDIR /usr/src/app
 
 CMD npm test
-