Print logs of failing tests

kokoro/linux/bazel/build.sh

@@ -7,11 +7,24 @@ set -ex
 use_bazel.sh latest
 bazel version
 
+# Print bazel testlogs to stdout when tests failed.
+function print_test_logs {
+  # TODO(yannic): Only print logs of failing tests.
+  testlogs_dir=$(bazel info bazel-testlogs)
+  testlogs=$(find "${testlogs_dir}" -name "*.log")
+  for log in $testlogs; do
+    cat "${log}"
+  done
+}
+
 # Change to repo root
 cd $(dirname $0)/../../..
 
 git submodule update --init --recursive
+
+trap print_test_logs EXIT
 bazel test :build_files_updated_unittest :protobuf_test --copt=-Werror --host_copt=-Werror
+trap - EXIT
 
 cd examples
 bazel build :all