Throw Exception in WP_Mock when handle_function fails

wpMockUndefinedFunctionTest.php

<?php

class SomeClass {
  public function do_something( $times ) {
    $user = wp_get_current_user();
    //...
    return true;
  }
}

class MyTestClass extends PHPUnit_Framework_TestCase {
  public function setUp() {
    \WP_Mock::setUp();
    $this->something = new SomeClass();
  }

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

  public function test_do_something() {
    \WP_Mock::wpFunction( 'wp_get_current_user' );
    $this->assertTrue( $this->something->do_something( 1 ) );
  }

  public function test_do_something_again() {
    $this->assertTrue( $this->something->do_something( 2 ) ); // This should cause an error but does not if run after the previous test
  }
}