Add test for mach bootstrap

This will ensure that Salt changes or refactors don't
break the important `./mach bootstrap` use case.

Make sure to test that bootstrap actually uses the local saltfs tree,
and doesn't just pull down saltfs via gitfs.

Use a new Travis node instead of the existing test node
to avoid any side effects caused by the bootstrapper,
and for added parallelism.

.travis.yml

@@ -77,6 +77,12 @@ matrix:
       os: linux
       sudo: required
       dist: trusty
+    # Not a Salt node, checks that mach bootstrap works
+    - env:
+        - SALT_NODE_ID=mach-bootstrap
+      os: linux
+      sudo: required
+      dist: trusty
 
 script: .travis/dispatch.sh
 

.travis/dispatch.sh

@@ -81,6 +81,21 @@ if [[ "${SALT_NODE_ID}" == "test" ]]; then
     # Run test suite separately for parallelism
     setup_venv
     ./test.py
+elif [[ "${SALT_NODE_ID}" == "mach-bootstrap" ]]; then
+    # Use system Python 2, not one of the supplemental ones Travis installs,
+    # so that `python-apt` is available
+    export PATH="/usr/bin:${PATH}"
+
+    # Run mach bootstrap test separately from `test` because it installs things
+    git clone --depth 1 https://github.com/servo/servo.git ../servo
+
+    # mach is intolerant of being run from other directories
+    cd ../servo
+    SERVO_SALTFS_ROOT="../saltfs" ./mach bootstrap --force
+    cd ../saltfs
+
+    # Check that the local saltfs tree was used
+    ./test.py servo.bootstrap
 elif [[ -n "${SALT_DOCKER_IMAGE:-}" ]]; then  # macOS bash is too old for `-v`
     printf "Using %s\n" "$(docker -v)"
 

Vagrantfile

@@ -46,7 +46,7 @@ Vagrant.configure(2) do |config|
         os_and_version = node['os'] + version
         puts "OS #{os_and_version} is not yet supported"
       end
-    elsif node_config[:id] != 'test'
+    elsif node_config[:id].start_with? 'servo-'
       node_config
     end
   end.compact.uniq.each do |node|

tests/servo/bootstrap.py

@@ -0,0 +1,13 @@
+import json
+
+from tests.util import Failure, Success
+
+
+def run():
+    with open('.servo/salt/etc/salt/minion') as config_file:
+        config = json.load(config_file)
+        ok = config['fileserver_backend'] == ['roots']
+        if ok:
+            return Success("mach bootstrap ran with the local saltfs tree")
+        else:
+            return Failure("mach bootstrap created bad config:", config)