devmode-test: make sure simple emerge works

We need emerge to work so we can install more binpkgs.

BUG=chromium:1197478
TEST=`./devinstall_test.py betty ../../../build/images/betty/latest/chromiumos_test_image.bin` works

Change-Id: Id0dc8c3f9dca10b7256cd43c59f4991d9314d7c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/2821653
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Dhanya Ganesh <dhanyaganesh@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/devmode-test/devinstall_test.py b/devmode-test/devinstall_test.py
index 32516dc..bac24ac 100755
--- a/devmode-test/devinstall_test.py
+++ b/devmode-test/devinstall_test.py
@@ -151,6 +151,9 @@
           self.device.run(['sudo', '-u', 'chronos', '--',
                            os.path.join(prefix, prog),
                            '-c', '"print(\'hello world\')"'])
+
+      # We need emerge to work so we can install more binpkgs.
+      self.device.run(['emerge', '--info'])
     except (cros_build_lib.RunCommandError,
             remote_access.SSHConnectionError) as e:
       self.devserver.PrintLog()