remove hhvm testing. failed with ...

Using worker: worker-linux-6-2.bb.travis-ci.org:travis-linux-13
git.1
$ git clone --depth=50 --branch=develop-2 git://github.com/auraphp/Aura.Sql_Schema.git auraphp/Aura.Sql_Schema
Cloning into 'auraphp/Aura.Sql_Schema'...
remote: Counting objects: 897, done.
remote: Compressing objects: 100% (363/363), done.
remote: Total 897 (delta 449), reused 845 (delta 412)
Receiving objects: 100% (897/897), 187.65 KiB, done.
Resolving deltas: 100% (449/449), done.
$ cd auraphp/Aura.Sql_Schema
git.3
$ git checkout -qf 95e2e84cbd81ba36abb13629390121154de07d52
$ phpenv global hhvm
$ php --version
HipHop VM v2.3.0 (rel)
Compiler: heads/HHVM-2.3-0-ga12fa4ac4dacbb45348a6ff2b3775f895883f934
Repo schema: 30349d0b2f68667d4e5a3fd291f2274c608f9e29
$ composer --version
Cannot open log file: /var/log/hhvm/error.log
HipHop Strict Warning: It is not safe to rely on the system's timezone settings. Please use the date.timezone setting, the TZ environment variable or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'UTC' for 'UTC/0.0/no DST' instead in phar://composer.phar/bin/../src/../src/Composer/Console/Application.php on line 65
Composer version 80499bb02418711b34bba59c1a6d8032429e5702 2013-12-06 12:32:19
before_script.1
$ mysql -e 'DROP DATABASE IF EXISTS test;'
before_script.2
$ mysql -e 'create database test;'
before_script.3
$ psql -c 'DROP DATABASE IF EXISTS test;' -U postgres
DROP DATABASE
before_script.4
$ psql -c 'create database test;' -U postgres
CREATE DATABASE
before_script.5
$ cd tests
$ phpunit
Cannot open log file: /var/log/hhvm/error.log
PHPUnit 3.7.28 by Sebastian Bergmann.
Configuration read from /home/travis/build/auraphp/Aura.Sql_Schema/tests/phpunit.xml
..F.....SSSSS.....
Time: 510 ms, Memory: 5.01Mb
There was 1 failure:
1) Aura\Sql_Schema\ColumnTest::test__set_state
Failed asserting that two strings are identical.
--- Expected
+++ Actual
@@ @@
 Aura\Sql_Schema\Column::__set_state(array(
-   'name' => 'cost',
-   'type' => 'numeric',
-   'size' => 10,
-   'scale' => 2,
-   'notnull' => true,
-   'default' => NULL,
-   'autoinc' => false,
-   'primary' => false,
+  '' . "\0" . '*' . "\0" . 'name' => 'cost',
+  '' . "\0" . '*' . "\0" . 'type' => 'numeric',
+  '' . "\0" . '*' . "\0" . 'size' => 10,
+  '' . "\0" . '*' . "\0" . 'scale' => 2,
+  '' . "\0" . '*' . "\0" . 'notnull' => true,
+  '' . "\0" . '*' . "\0" . 'default' => NULL,
+  '' . "\0" . '*' . "\0" . 'autoinc' => false,
+  '' . "\0" . '*' . "\0" . 'primary' => false,
 ))
phar://phpunit-3.7.28.phar/phpunit/Framework/Constraint.php:147
phar://phpunit-3.7.28.phar/phpunit/Framework/Constraint/IsIdentical.php:132
phar://phpunit-3.7.28.phar/phpunit/Framework/Assert.php:2134
phar://phpunit-3.7.28.phar/phpunit/Framework/Assert.php:1095
/home/travis/build/auraphp/Aura.Sql_Schema/tests/src/ColumnTest.php:79
phar://phpunit-3.7.28.phar/phpunit/Framework/TestCase.php:983
phar://phpunit-3.7.28.phar/phpunit/Framework/TestCase.php:838
phar://phpunit-3.7.28.phar/phpunit/Framework/TestResult.php:648
phar://phpunit-3.7.28.phar/phpunit/Framework/TestCase.php:783
phar://phpunit-3.7.28.phar/phpunit/Framework/TestSuite.php:775
phar://phpunit-3.7.28.phar/phpunit/Framework/TestSuite.php:745
phar://phpunit-3.7.28.phar/phpunit/Framework/TestSuite.php:705
phar://phpunit-3.7.28.phar/phpunit/TextUI/TestRunner.php:349
phar://phpunit-3.7.28.phar/phpunit/TextUI/Command.php:176
phar://phpunit-3.7.28.phar/phpunit/TextUI/Command.php:129
FAILURES!
Tests: 18, Assertions: 55, Failures: 1, Skipped: 5.
The command "phpunit" exited with 1.
Done. Your build exited with 1.