[ci] check formatting

Author: gnzlbg

.appveyor.yml

@@ -15,12 +15,14 @@ install:
   - if NOT "%TARGET%" == "x86_64-pc-windows-msvc" rustup target add %TARGET%
   - rustc -vV
   - cargo -vV
+  - cargo install rustfmt-nightly
 
 build: false
 
 test_script:
   - cargo test --target %TARGET%
   - cargo test --target %TARGET% --release
+  - cargo fmt -- --write-mode=diff
 
 branches:
   only:

.travis.yml

@@ -20,6 +20,7 @@ install:
 
 script:
   - cargo generate-lockfile
+  - cargo install rustfmt-nightly
   - ci/run-docker.sh $TARGET
 
 notifications:

ci/run.sh

@@ -4,3 +4,4 @@ set -ex
 
 cargo test --target $TARGET
 cargo test --release --target $TARGET
+cargo fmt -- --write-mode=diff

rustfmt.toml

@@ -0,0 +1 @@
+max_width = 79