[IMP] Install testing requirements into separate image.

Fixes #277

Author: amh-mw

16.0/test.Dockerfile

@@ -0,0 +1,11 @@
+ARG version=16
+ARG image=odoo:${version}
+FROM ${image}
+
+# Install testing requirements
+USER root
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends chromium && \
+    rm -rf /var/lib/apt/lists/*
+RUN pip3 install websocket-client
+USER odoo

17.0/test.Dockerfile

@@ -0,0 +1,14 @@
+ARG version=17
+ARG image=odoo:${version}
+FROM ${image}
+
+# Install testing requirements
+USER root
+RUN curl -o google-chrome-stable_current_amd64.deb -sSL https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb && \
+    apt-get update && \
+    DEBIAN_FRONTEND=noninteractive \
+    apt-get install -y --no-install-recommends \
+        ./google-chrome-stable_current_amd64.deb \
+        python3-websocket \
+    && rm -rf /var/lib/apt/lists/* ./google-chrome-stable_current_amd64.deb
+USER odoo

18.0/test.Dockerfile

@@ -0,0 +1,14 @@
+ARG version=18
+ARG image=odoo:${version}
+FROM ${image}
+
+# Install testing requirements
+USER root
+RUN curl -o google-chrome-stable_current_amd64.deb -sSL https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb && \
+    apt-get update && \
+    DEBIAN_FRONTEND=noninteractive \
+    apt-get install -y --no-install-recommends \
+        ./google-chrome-stable_current_amd64.deb \
+        python3-websocket \
+    && rm -rf /var/lib/apt/lists/* ./google-chrome-stable_current_amd64.deb
+USER odoo