Cache the downloaded .cvd files in Travis

.travis.yml

@@ -9,15 +9,22 @@ sudo: required
 services:
   - docker
 
+cache:
+  directories:
+    - test/cookbooks/clamav_test/files
+
+env:
+  - CVD_PATH=test/cookbooks/clamav_test/files
+
 install:
   - curl -L https://www.chef.io/chef/install.sh | sudo bash -s -- -P chefdk
   - chef exec bundle install --without=development integration
 
 before_script:
-  - mkdir -p test/cookbooks/clamav_test/files
-  - wget -P test/cookbooks/clamav_test/files http://database.clamav.net/main.cvd
-  - wget -P test/cookbooks/clamav_test/files http://database.clamav.net/daily.cvd
-  - wget -P test/cookbooks/clamav_test/files http://database.clamav.net/bytecode.cvd
+  - mkdir -p $CVD_PATH
+  - "[ -e $CVD_PATH/main.cvd ] || wget -P $CVD_PATH http://database.clamav.net/main.cvd"
+  - "[ -e $CVD_PATH/daily.cvd ] || wget -P $CVD_PATH http://database.clamav.net/daily.cvd"
+  - "[ -e $CVD_PATH/bytecode.cvd ] || wget -P $CVD_PATH http://database.clamav.net/bytecode.cvd"
   - cp .kitchen.travis.yml .kitchen.local.yml
 
 script: