test_docker_compose.py: Test the volume mount feature

Extend docker_compose_test() to expose /bin on the host to the container
through a volume mount and verify that /bin/busybox can be downloaded and
contains the right data.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit aa31d10808)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/testing/conf/docker-compose.yml

@@ -2,6 +2,8 @@ version: '3'
 services:
   busybox:
     image: "busybox:latest"
-    command: httpd -f -h /etc/
+    command: httpd -f -h /www/
     ports:
       - "80:80"
+    volumes:
+      - "/bin:/www"

support/testing/tests/package/test_docker_compose.py

@@ -45,7 +45,8 @@ class TestDockerCompose(infra.basetest.BRTest):
         self.assertRunOk('docker-compose up -d', 120)
         # container may take some time to start
         self.assertRunOk('while ! docker inspect root_busybox_1 2>&1 >/dev/null; do sleep 1; done', 120)
-        self.assertRunOk('wget http://127.0.0.1/resolv.conf', 120)
+        self.assertRunOk('wget -O /tmp/busybox http://127.0.0.1/busybox', 120)
+        self.assertRunOk('cmp /bin/busybox /tmp/busybox', 120)
 
     def test_run(self):
         kernel = os.path.join(self.builddir, "images", "bzImage")