anish@anish-Inspiron-3537:~/Desktop/mozilla-central-55f3224d7513$ ./mach mochitest-browser browser/components/shell/test/
Build configuration changed. Regenerating backend.
Reticulating splines...
Finished reading 2748 moz.build files in 1.93s
Processed into 7569 build config descriptors in 1.58s
Backend executed in 2.61s
2265 total backend files; 0 created; 0 updated; 2265 unchanged; 0 deleted; 138 -> 852 Makefile
Total wall time: 6.47s; CPU time: 6.00s; Efficiency: 93%; Untracked: 0.35s
From _tests: Kept 34030 existing; Added/updated 0; Removed 0 files and 0 directories.
testpath: browser/components/shell/test
SUITE-START | Running 2 tests
pk12util: PKCS12 IMPORT SUCCESSFUL
MochitestServer : launching [u'/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/dist/bin/xpcshell', '-g', u'/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/dist/bin', '-v', '170', '-f', u'/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/dist/bin/components/httpd.js', '-e', "const _PROFILE_PATH = '/tmp/tmpVQx3Rz.mozrunner'; const _SERVER_PORT = '8888'; const _SERVER_ADDR = '127.0.0.1'; const _TEST_PREFIX = undefined; const _DISPLAY_RESULTS = false;", '-f', '/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/server.js']
runtests.py | Server pid: 7399
runtests.py | Websocket server pid: 7401
runtests.py | SSL tunnel pid: 7403
Stopping web server
Stopping web socket server
Stopping ssltunnel
Error running mach:

    ['mochitest-browser', 'browser/components/shell/test/']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.

You should consider filing a bug for this issue.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

ParseError: run-if is no longer supported, use skip-if

  File "/home/anish/Desktop/mozilla-central-55f3224d7513/testing/mochitest/mach_commands.py", line 670, in run_mochitest_browser
    return self.run_mochitest(test_paths, 'browser', **kwargs)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/testing/mochitest/mach_commands.py", line 793, in run_mochitest
    test_paths=test_paths, suite=flavor, **kwargs)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/testing/mochitest/mach_commands.py", line 394, in run_desktop_test
    result = runner.runTests(options)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/runtests.py", line 1776, in runTests
    result = self.runMochitests(options, onLaunch)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/runtests.py", line 1724, in runMochitests
    result = self.doTests(options, onLaunch, testsToRun)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/runtests.py", line 1847, in doTests
    testURL = self.buildTestPath(options, testsToFilter)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/runtests.py", line 683, in buildTestPath
    tests = self.getActiveTests(options, disabled)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/runtests.py", line 1651, in getActiveTests
    tests = manifest.active_tests(disabled=disabled, options=options, **info)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/manifestparser.py", line 1171, in active_tests
    self.filter(values, tests)
  File "/home/anish/Desktop/mozilla-central-55f3224d7513/obj-x86_64-unknown-linux-gnu/_tests/testing/mochitest/manifestparser.py", line 1105, in filter
    raise ParseError('run-if is no longer supported, use skip-if')
anish@anish-Inspiron-3537:~/Desktop/mozilla-central-55f3224d7513$ ./mach mochitest-browser browser/components/shell/test/