Enable ChainerX C++ test in Travis CI

.travis.yml

@@ -40,6 +40,13 @@ matrix:
       - CHAINER_TRAVIS_TEST="chainer"
       - MATRIX_EVAL="CC=gcc-5 && CXX=g++-5"
 
+    - name: "Ubuntu16.04 Py35 + ChainerX (C++ test)"
+      dist: xenial
+      python: "3.5"
+      env:
+      - CHAINER_TRAVIS_TEST="chainerx-cpp"
+      - MATRIX_EVAL="CC=gcc-5 && CXX=g++-5"
+
     - name: "macOS Py35"
       os: osx
       language: generic

scripts/ci/travis/run-tests.sh

@@ -114,6 +114,21 @@ case "${CHAINER_TRAVIS_TEST}" in
                 ;;
         esac
         ;;
+
+    "chainerx-cpp")
+        case "$phase" in
+            before_install)
+            ;;
+            install)
+                run_prestep chainerx_cmake
+                run_prestep chainerx_make
+            ;;
+            script)
+                run_step chainerx_ctest
+            ;;
+        esac
+        ;;
+
     *)
         echo "Unknown value of CHAINER_TRAVIS_TEST: ${CHAINER_TRAVIS_TEST}" >&2
         exit 1

scripts/ci/travis/steps.sh

@@ -156,6 +156,37 @@ step_docs() {
 }
 
 
+step_chainerx_cmake() {
+    CHAINERX_BUILD_DIR="$WORK_DIR"/chainerx_build
+    mkdir -p "$CHAINERX_BUILD_DIR"
+    pushd "$CHAINERX_BUILD_DIR"
+
+    cmake \
+        -DCMAKE_BUILD_TYPE=Debug \
+        -DCHAINERX_BUILD_CUDA=OFF \
+        -DCHAINERX_BUILD_TEST=ON \
+        -DCHAINERX_BUILD_PYTHON=OFF \
+        -DCHAINERX_WARNINGS_AS_ERRORS=ON \
+        -DCMAKE_INSTALL_PREFIX="$WORK_DIR"/install_target \
+        "$REPO_DIR"/chainerx_cc
+    popd
+
+    echo "CHAINERX_BUILD_DIR=\"$CHAINERX_BUILD_DIR\"" >> "$CHAINER_BASH_ENV"
+}
+
+
+step_chainerx_make() {
+    make -C "$CHAINERX_BUILD_DIR" --output-sync
+}
+
+
+step_chainerx_ctest() {
+    pushd "$CHAINERX_BUILD_DIR"
+    ctest -V
+    popd
+}
+
+
 step_before_install_chainerx_style_check_deps() {
     [ $TRAVIS_OS_NAME = "linux" ]  # currently only tested in linux