language: rust
rust:
  - stable
  - beta
  - nightly
before_script:
  - bash -c 'if [[ "$TRAVIS_RUST_VERSION" == "nightly"* ]]; then rustup component add rustfmt-preview; fi'
script:
  - bash -c 'if [[ "$TRAVIS_RUST_VERSION" == "nightly"* ]]; then cargo fmt --all -- --check; fi'
  - cargo build
  - cargo test
matrix:
  allow_failures:
    - rust: nightly