Check out the pull request below, where I've added assertions for the runtime instance var to make it more explicit. Not doing any checks on the $result variable is intentional - other tests cover that case, and so I figured this test should focus only on the thing it's intended to test.

However, if you want me to add an assertion like `$this->assertInternalType('array', $result);` the let me know and I'll add it to the PR below.