It's actually three tests that are failing:

PHPUnit 4.1.3 by Sebastian Bergmann.

Configuration read from /srv/mediawiki/tests/phpunit/suite.xml

FFF.................................................

Time: 38.4 seconds, Memory: 20.72Mb

There were 3 failures:

1. ApiFlickrBlacklistTest::testBlacklistMatchByNsid

blacklist does not match
Failed asserting that two strings are equal.

• Expected

+++ Actual
@@ @@
-'bad'
+'ok'

/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:186
/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:52
/srv/mediawiki/tests/phpunit/MediaWikiTestCase.php:133
/srv/mediawiki/tests/phpunit/MediaWikiPHPUnitCommand.php:42

2. ApiFlickrBlacklistTest::testBlacklistMatchByUsername

blacklist does not match
Failed asserting that two strings are equal.

• Expected

+++ Actual
@@ @@
-'bad'
+'ok'

/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:186
/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:70
/srv/mediawiki/tests/phpunit/MediaWikiTestCase.php:133
/srv/mediawiki/tests/phpunit/MediaWikiPHPUnitCommand.php:42

3. ApiFlickrBlacklistTest::testBlacklistMatchWithMultipleItems

blacklist does not match
Failed asserting that two strings are equal.

• Expected

+++ Actual
@@ @@
-'bad'
+'ok'

/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:186
/srv/mediawiki/extensions/UploadWizard/tests/phpunit/ApiFlickrBlacklistTest.php:82
/srv/mediawiki/tests/phpunit/MediaWikiTestCase.php:133
/srv/mediawiki/tests/phpunit/MediaWikiPHPUnitCommand.php:42

FAILURES!
Tests: 52, Assertions: 70, Failures: 3.

This appears to be caused by not having network access to the tests (Apparently it treats unable to read flickr api response as image is ok...)

Change 141582 had a related patch set uploaded by Brian Wolff:
Make unit tests be skipped if no network.

https://gerrit.wikimedia.org/r/141582

Change 141582 merged by jenkins-bot:
Make unit tests be skipped if no network.

https://gerrit.wikimedia.org/r/141582

All patches mentioned in this report were merged - is there more work left to do here (if yes: please reset the bug report status to NEW or ASSIGNED), or can you close this ticket as RESOLVED FIXED?

This looks fixed to me.