@halton As I know, it is by design, adding a specific target 'xwalk_core_test_apk' would make thing clean and work , but it is problematic when a file in asserts folder is updated. The target would not be run again, so the generated apk doesn't contain the updated version, and we didn't find a proper way to fix it. This is why we use multi-line copy statement, 

@yongsheng Please confirm it.

@DonnaWuDongxia Can you have a check? e.g. update one of files in assets folder, and check it if the updated version is packaged into the final XWalkCoreTest.apk.