Add the bazel build as one of the PR-blocking builds.

.travis.yml

@@ -37,6 +37,30 @@ matrix:
         - libvpx-dev            # For toxav.
     install:       .travis/$JOB install
     script:        .travis/$JOB script
+  - stage: "Stage 1"
+    env: JOB=bazel-linux
+    compiler: clang
+    addons:
+      apt:
+        packages:
+        - libcv-dev             # For av_test.
+        - libhighgui-dev        # For av_test.
+        - libopencv-contrib-dev # For av_test.
+        - portaudio19-dev       # For av_test.
+    before_install:
+    # Clear bazel installation.
+    - rm -rf $HOME/.cache/bazel/_bazel_$USER/install
+    # Get toktok-stack, which contains the bazel workspace.
+    - cd ..
+    - git clone https://github.com/TokTok/toktok-stack
+    - rm -rf toktok-stack/c-toxcore
+    - mv c-toxcore toktok-stack/
+    - cd toktok-stack/c-toxcore
+    install:       .travis/$JOB install
+    script:        .travis/$JOB script
+    before_cache:
+    # Clear bazel installation.
+    - rm -rf $HOME/.cache/bazel/_bazel_$USER/install
   - stage: "Stage 1"
     if: type IN (push, api, cron)
     env: JOB=cmake-win32
@@ -76,6 +100,7 @@ matrix:
 
 cache:
   directories:
+  - $HOME/.cache/bazel
   - $HOME/cache
   - /opt/freebsd/cache
 

.travis/bazel-linux

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+ACTION="$1"
+
+set -eu
+
+travis_install() {
+  # Get bazel.
+  wget https://github.com/bazelbuild/bazel/releases/download/0.15.0/bazel-0.15.0-installer-linux-x86_64.sh
+  chmod +x bazel-0.15.0-installer-linux-x86_64.sh
+  ./bazel-0.15.0-installer-linux-x86_64.sh --user
+  echo 'build --jobs=4 --curses=no --verbose_failures' >> $HOME/.bazelrc
+  echo "import %workspace%/tools/bazelrc/linux-$CC" >> $HOME/.bazelrc
+}
+
+travis_script() {
+  # Run the tests, but if they fail, at least we should be able to build.
+  bazel test //c-toxcore/... || bazel build //c-toxcore/...
+}
+
+if [ "-z" "$ACTION" ]; then
+  "travis_script"
+else
+  "travis_$ACTION"
+fi