Refactored travis config

.travis.yml

@@ -1,16 +1,50 @@
-sudo: false
-dist: trusty
 language: rust
+sudo: false
 cache: cargo
+
 rust:
-  - nightly
-  - beta
-  - stable
-before_script:
-  - rustup component add rustfmt
-script:
-  - cargo fmt --all -- --check
-  - cargo build
-  - cargo build --release
-  - cargo test
-  - cargo test --release
+- stable
+- beta
+- nightly
+
+os:
+- linux
+- osx
+
+# Set global environment only
+env:
+  global:
+  - RUST_BACKTRACE=1
+
+notifications:
+  email:
+    on_success: never
+
+matrix:
+  fast_finish: true
+  allow_failures:
+  - rust: nightly
+
+  include:
+  - name: 'Rust: format check'
+    rust: stable
+    install:
+    - rustup component add rustfmt
+    script:
+    - cargo fmt --verbose --all -- --check
+
+  - name: 'Rust: style check'
+    if: env(ENABLE_CLIPPY) = 1
+    rust: stable
+    install:
+    - rustup component add clippy
+    script:
+    - cargo clippy --verbose --all -- -D warnings
+
+  - name: 'Rust: code coverage'
+    rust: stable
+    os: linux
+    install:
+    - cargo install cargo-tarpaulin
+    script:
+    - cargo tarpaulin --verbose --ciserver travis-ci --coveralls $TRAVIS_JOB_ID