Use ccache for faster testing

.travis.sh

@@ -24,6 +24,9 @@ function travis_time_end {
 
 apt-get update -qq && apt-get install -qq -y -q wget sudo lsb-release gnupg # for docker
 
+# Setup ccache
+apt-get install -qq -y -q ccache
+export PATH=/usr/lib/ccache:$PATH
 
 travis_time_start setup.before_install
 #before_install:

.travis.yml

@@ -1,6 +1,9 @@
 sudo: false
 dist: trusty
 language: generic
+cache:
+  directories:
+    - $HOME/.ccache
 env:
   global:
     - ROS_DISTRO=lunar
@@ -17,7 +20,7 @@ before_install:
   - export ROS_PARALLEL_JOBS='-j8 -l6'
 script:
   - echo "Testing branch $TRAVIS_BRANCH of $REPOSITORY_NAME"
-  - docker run --rm -i -v $CI_SOURCE_PATH:$CI_SOURCE_PATH -e "CI_SOURCE_PATH=$CI_SOURCE_PATH" -e "HOME=$HOME" -e "ROS_DISTRO=$ROS_DISTRO" -e "ROS_PARALLEL_JOBS=$ROS_PARALLEL_JOBS" -e "DOCKER_IMAGE=$DOCKER_IMAGE" -t $DOCKER_IMAGE sh -c "cd $CI_SOURCE_PATH; ./.travis.sh"
+  - docker run --rm -i -v $CI_SOURCE_PATH:$CI_SOURCE_PATH -v $HOME:$HOME -e "CI_SOURCE_PATH=$CI_SOURCE_PATH" -e "HOME=$HOME" -e "ROS_DISTRO=$ROS_DISTRO" -e "ROS_PARALLEL_JOBS=$ROS_PARALLEL_JOBS" -e "DOCKER_IMAGE=$DOCKER_IMAGE" -t $DOCKER_IMAGE sh -c "cd $CI_SOURCE_PATH; ./.travis.sh"
 after_failure:
   - find ${HOME}/.ros/test_results -type f -exec echo "== {} ==" \; -exec cat {} \;
   - for file in ${HOME}/.ros/log/rostest-*; do echo "=== $file ==="; cat $file; done