Total shows 200%. If this is intentional I'm not understanding it :)
If one of the classes is not complety covered it shows 1/2 100% so I'm fairly sure thats a bug :)

cat Trait.php
<?php
class TraitUser {
use MyTrait;
}
trait MyTrait {
public function foo() {
return 1;
}
}
cat TraitTest.php
<?php
require __DIR__ . '/Trait.php';
class TraitTest extends PHPUnit_Framework_TestCase {
public function testTrait() {
$x = new TraitUser();
$this->assertSame(1, $x->foo());
}
}
Running:
phpunit --coverage-html foo TraitTest.php && firefox foo/index.html