language: rust
matrix:
  include:
    - rust: stable
      os: linux
    - rust: stable
      os: osx
script:
  - cargo test

language: rust
matrix:
  include:
    - rust: stable
    - rust: stable
      os: osx
    - rust: beta
    - rust: nightly
script:
  - cargo test

Add Rust beta and nightly
[Travis] Add Rust beta and nightly
