update_engine: Test update_engine printouts

These tests are added to enforce sensitive variables stay invariant
with no room or future mistakes to occur again on breaking autotest
and cros flash process.

BUG=chromium:871340
TEST=FEATURES="test" emerge-$BOARD update_engine update_engine-client
TEST=/usr/bin/update_engine_client --status
TEST=cros flash $TEST_IP ../build/image/... # works

Change-Id: Ibcce5c1dee56cf5bca201a86a143a87b033605bc
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/1732410
Tested-by: Jae Hoon Kim <kimjae@chromium.org>
Auto-Submit: Jae Hoon Kim <kimjae@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Jae Hoon Kim <kimjae@chromium.org>
diff --git a/Android.bp b/Android.bp
index e9b7b13..2e215c5 100644
--- a/Android.bp
+++ b/Android.bp
@@ -661,6 +661,7 @@
         "payload_generator/zip_unittest.cc",
         "testrunner.cc",
         "update_attempter_android_unittest.cc",
+        "update_status_utils_unittest.cc",
     ],
 }