preload.php

<?php
namespace Stagehand\TestRunner\Util;

require_once 'PHPUnit/Framework/Assert/Functions.php';

spl_autoload_register(function ($name) {

    $fn = __DIR__ . DIRECTORY_SEPARATOR . strtr($name, '_', '/') . '.php';

    if (file_exists($fn))
    {
        return include $fn;
    }

    return false;
});

class FailureTrace
{
    /**
     * @param array $testClassSuperTypes
     * @param \Exception $e
     * @param \ReflectionClass $class
     * @return array
     */
    public static function findFileAndLineOfFailureOrError(array $testClassSuperTypes, \Exception $e, \ReflectionClass $class)
    {
        if (in_array($class->getName(), $testClassSuperTypes)) return;
        if ($e->getFile() == $class->getFileName()) {
            return array($e->getFile(), $e->getLine());
        }
        foreach ($e->getTrace() as $trace) {
            if (array_key_exists('file', $trace) && $trace['file'] == $class->getFileName()) {
                return array($trace['file'], $trace['line']);
            }
        }
        //*
        foreach ($class->getTraits() as $trait) {
            $ret = self::findFileAndLineOfFailureOrError($testClassSuperTypes, $e, $trait);
            if ($ret) {
                return $ret;
            }
        }
        /**/
        return self::findFileAndLineOfFailureOrError($testClassSuperTypes, $e, $class->getParentClass());
    }

    /**
     * @param array $backtrace
     * @return string
     */
    public static function buildFailureTrace(array $backtrace)
    {
        $failureTrace = '';
        for ($i = 0, $count = count($backtrace); $i < $count; ++$i) {
            if (!array_key_exists('file', $backtrace[$i])) {
                continue;
            }

            $failureTrace .=
            $backtrace[$i]['file'] .
            ':' .
            (array_key_exists('line', $backtrace[$i]) ? $backtrace[$i]['line']
                    : '?') .
                    PHP_EOL;
        }

        return $failureTrace;
    }
}

TraitSampleTest.php

<?php
class TraitSampleTest extends PHPUnit_Framework_TestCase
{
    use TraitSampleTrait;
    
    protected function getOne()
    {
        return 2;
    }
}

TraitSampleTrait.php

<?php
trait TraitSampleTrait
{
    abstract protected function getOne();

    function testOne()
    {
        assertEquals(1, $this->getOne());
    }
}