【Rust日报】 2019-06-21：Typestate 模式

#!/usr/bin/env bash

if [ -z "$(git status --porcelain)" ] ; then
  commit=$(git rev-parse HEAD)
  docker build --tag image_name:$commit .
else
  exit 1
fi

tests:
  # builds a docker image when git repo is clean
  - steps:
    - command: /usr/bin/git status --porcelain
      stdout: ""
    - command: /usr/bin/git rev-parse HEAD
      stdout: "mock_commit_hash\n"
    - /usr/bin/docker build --tag image_name:mock_commit_hash .
  # aborts when git repo is not clean
  - steps:
    - command: /usr/bin/git status --porcelain
      stdout: " M some-file"
    exitcode: 1