Use the shared Docker image at Travis

.travis.yml

@@ -4,6 +4,8 @@ services:
   - docker
 
 before_install:
-  - docker build -t yast-devel-tw .
+  - docker build -t yast-test-image .
 script:
-  - docker run -it -e TRAVIS_JOB_ID="$TRAVIS_JOB_ID" yast-devel-tw ./.travis.sh
+  # the "yast-travis" script is included in the base yastdevel/ruby-tw image
+  # see https://github.com/yast/docker-yast-ruby-tw/blob/master/yast-travis
+  - docker run -it -e TRAVIS_JOB_ID="$TRAVIS_JOB_ID" yast-test-image yast-travis

Dockerfile

@@ -1,27 +1,3 @@
-FROM opensuse:tumbleweed
-RUN zypper ar -f http://download.opensuse.org/repositories/YaST:/Head/openSUSE_Tumbleweed/ yast
-RUN zypper --gpg-auto-import-keys --non-interactive in \
-      fdupes \
-      grep \
-      yast2-devtools \
-      perl-XML-Writer \
-      yast2 \
-      yast2-country-data \
-      yast2-devtools \
-      autoyast2-installation \
-      'rubygem(rspec)' \
-      'rubygem(yast-rake)' \
-      augeas-lenses \
-      'rubygem(cfa)' \
-      'rubygem(gettext)' \
-      'rubygem(simplecov)' \
-      update-desktop-files \
-      git \
-      rpm-build \
-      which
-# FIXME: fix the dependency issues in YaST:Head and install them via zypper
-# FIXME: switch to Rubocop 0.41.2 as the rest of YaST
-RUN gem install --no-document coveralls yard rubocop:0.29.1
+FROM yastdevel/ruby-tw
 COPY . /tmp/sources
-WORKDIR /tmp/sources