WP_Mock do_action failure

composer.json

{
    "require-dev": {
        "10up/wp_mock": "dev-master"
    }
}

my-Test.php

<?php

function my_wp_function() {
  do_action( 'foo', 'bar' );
}

class MyTest extends PHPUnit_Framework_TestCase
{
  public function setUp() {
    \WP_Mock::setUp();
  }

  public function tearDown() {
    \WP_Mock::tearDown();
  }

  public function testRunsCorrectly()
  {
    my_wp_function();
    $this->assertEquals(1, 1);
  }
}