Build API: Automatic copying of files into the chroot.

Implemented in the VM test endpoint for the vm image itself.

BUG=chromium:966903
TEST=run_tests

Change-Id: Iab179101a933373ca1bdca5b4046b8f561a538a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1639598
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Evan Hernandez <evanhernandez@chromium.org>
diff --git a/scripts/build_api_unittest.py b/scripts/build_api_unittest.py
index 957e73c..99bde54 100644
--- a/scripts/build_api_unittest.py
+++ b/scripts/build_api_unittest.py
@@ -103,7 +103,7 @@
     service_method = '%s/%s' % (service, method)
     self.router.Route(service, method, self.input_file, self.output_file)
 
-    self.assertCommandContains(['build_api', service_method])
+    self.assertCommandContains(['build_api', service_method], enter_chroot=True)
 
   def testInsideServiceOutsideMethodInsideChroot(self):
     """Test inside chroot for outside method raises an error."""
@@ -145,4 +145,4 @@
     service_method = '%s/%s' % (service, method)
     self.router.Route(service, method, self.input_file, self.output_file)
 
-    self.assertCommandContains(['build_api', service_method])
+    self.assertCommandContains(['build_api', service_method], enter_chroot=True)