After updating unit tests to be compatible with PHPUnit 6, arc unit fails what leads to inability to create a differential review.
= Reproduction steps
1. create new directory, init git and set up necessary files:
```lang=json, name=composer.json
{
"require": {
"phpunit/phpunit": "^6.0"
}
}
```
```lang=json, name=.arcconfig
{
"unit.engine": "PhpunitTestEngine",
"unit.phpunit.binary": "vendor/bin/phpunit"
}
```
```lang=php, name=dataTest.php
<?php
use PHPUnit\Framework\TestCase;
class DataTest extends TestCase
{
public function testAdd()
{
$this->assertEquals(4, 2 + 2);
}
}
```
2. run `composer install`
3. run `arc unit dataTest.php --trace`:
```
13:41 $ arc unit dataTest.php --trace
...
>>> [0] <exec> $ which 'vendor/bin/phpunit'
<<< [0] <exec> 2,203 us
>>> [1] <exec> $ vendor/bin/phpunit -d display_errors=stderr --log-json '/tmp/801ns8shcgkc00k0/17490-AUKPdN' --coverage-clover '/tmp/47h5jepdu2as084s/17490-QK7yko' '/home/ali/arctest/dataTest.php'
<<< [1] <exec> 37,234 us
BROKEN /home/ali/arctest/dataTest.php
```
= Test ^5 Unit test version
run the following commands:
```
rm -rf vendors
rm composer.lock
sed -i 's/6.0/5.0/g' composer.json
composer install
arc unit dataTest.php
```
```
13:45 $ arc unit dataTest.php
PASS 2ms★ DataTest::testAdd
```
= The issue
PHPUnit changelog for version 6.0 says:
```
* Removed the `--log-json` commandline option (deprecated in PHPUnit 5.7)
```
This command line option is used in standard `PhpunitTestEngine`:
https://github.com/phacility/arcanist/blob/9e82ef979e8148c43b9b8439025d505b1219e213/src/unit/engine/PhpunitTestEngine.php#L67
= Arc version
```
arcanist 129d51fa0936c9bae48fadf3a3f39e26d69d24da (18 May 2017)
libphutil a900d7b63e954e221efe140f0f33d3d701524aae (23 Apr 2017)
```