Have Travis-CI also test on stable Rust

Author: SimonSapin

.travis.yml

@@ -4,7 +4,10 @@ branches:
       - servo
 
 language: rust
-rust: nightly
+rust:
+    - nightly
+    - beta
+    - stable
 script: scripts/travis-build.sh
 after_success: curl https://raw.githubusercontent.com/kmcallister/travis-doc-upload/master/travis-doc-upload.sh | sh
 

scripts/travis-build.sh

@@ -10,11 +10,20 @@
 
 set -ex
 
+# Test without unstable first, to make sure src/tree_builder/rules.expanded.rs is up-to-date.
 cargo test --no-run
 cargo test | ./scripts/shrink-test-output.py
 r=${PIPESTATUS[0]}
 if [ $r -ne 0 ]; then exit $r; fi
 
-cargo test --manifest-path capi/Cargo.toml
+if [ $TRAVIS_RUST_VERSION = nightly ]
+then
+    cargo test --no-run --features unstable
+    cargo test --features unstable | ./scripts/shrink-test-output.py
+    r=${PIPESTATUS[0]}
+    if [ $r -ne 0 ]; then exit $r; fi
+
+    cargo test --manifest-path capi/Cargo.toml
+fi
 
 cargo doc