Ankit, The failure seems related to your commit:
FAIL: llbuild-unit :: BuildSystem/BuildSystemTests/BuildSystemTaskTests.staleFileRemovalWithManyFiles (113 of 158)
<>******************** TEST 'llbuild-unit :: BuildSystem/BuildSystemTests/BuildSystemTaskTests.staleFileRemovalWithManyFiles' FAILED ********************
Please confirm / advise. I can revert it to unblock the bots.
Regards,
—Joe | | 
shajrawi@apple.com | 
(+1) 408-930-5203
···
On May 19, 2017, at 10:42 AM, no-reply@swift.org wrote:
[FAILURE] oss-swift-incremental-RA-osx [#10262]
Build URL: https://ci.swift.org/job/oss-swift-incremental-RA-osx/10262/
Project: oss-swift-incremental-RA-osx
Date of build: Fri, 19 May 2017 10:12:45 -0700
Build duration: 29 min
Identified problems:Regression test failed: This build failed because a regression test in the test suite FAILed. Below is a list of all errors:
Indication 1 <https://ci.swift.org//job/oss-swift-incremental-RA-osx/10262/consoleFull#-1366378527fca400bf-2f4a-462e-b517-e058d770b2d7>
Tests:Name: Swift(macosx-x86_64)
Failed: 0 test(s), Passed: 9413 test(s), Total: 9413 test(s)
Name: Swift-Unit
Failed: 0 test(s), Passed: 492 test(s), Total: 492 test(s)Changes
Commit fc3d9db5dcce5c5b5ceb7538efeb294445235b54 by Ankit Aggarwal:
[BuildSystem] Check command result in MockBuildSystemDelegateedit: unittests/BuildSystem/BuildSystemTaskTests.cpp
edit: unittests/BuildSystem/MockBuildSystemDelegate.h