Eris\ExampleEnd2EndTest::runExample PHP Method

    private function runExample($testFile)
    {
        $this->testFile = $testFile;
        $examplesDir = realpath(__DIR__ . '/../examples');
        $samplesTestCase = $examplesDir . '/' . $testFile;
        $logFile = tempnam(sys_get_temp_dir(), 'phpunit_log_');
        $environmentVariables = [];
        foreach ($this->environment as $name => $value) {
            $environmentVariables[] .= "{$name}={$value}";
        }
        $phpunitCommand = implode(" ", $environmentVariables) . " vendor/bin/phpunit --log-junit {$logFile} {$samplesTestCase}";
        exec($phpunitCommand, $output);
        $contentsOfXmlLog = file_get_contents($logFile);
        if (!$contentsOfXmlLog) {
            $this->fail("It appears the command" . PHP_EOL . $phpunitCommand . PHP_EOL . "has crashed without leaving a log for us to analyze." . PHP_EOL . "This was its output: " . implode(PHP_EOL, $output) . PHP_EOL);
        }
        $this->results = new SimpleXMLElement($contentsOfXmlLog);
    }