language: rust
rust:
    - 1.31.0
    - stable
    - beta
    - nightly
cache: cargo
script:
  - if [ "$TRAVIS_RUST_VERSION" == "1.31.0" ]; then cp Cargo.lock.ci Cargo.lock; fi
  - cargo test
  - cargo test --features backtrace
  - cargo check --no-default-features