Test wercker cache. Run two builds with this wercker.yml and during the second build you will see the file show up in the first step.

wercker.yml

box: ubuntu
build:
  steps:
    - script: 
        name: ls -la
        code: ls -la $WERCKER_CACHE_DIR
        
    - script: 
        name: print
        code: echo "this is a test" > $WERCKER_CACHE_DIR/static
        
    - script: 
        name: ls -la
        code: ls -la $WERCKER_CACHE_DIR