How to find my ui-grid's ID?

I'm using gridTestUtils.spec.js functions to perform e2e tests on my ui-grid. The issue is you have to specify the gridId as a parameter. I've tried a lot of different Ids but none of them actually work.

As an example I'm trying to do gridTestUtils.getRow( 'grid', 3 );

I don't know what 'grid' is supposed to be. I can't see it anywhere in the element. I've already tried 'myGrid, grid, vm.gridOptions, vm.gridOptions.data, grid-container'...

I have never specified the grid's name. How am I supposed to know what the id of it is?