tests failing, will investigate

I think #714 is invalid; there's a deliberate use of a custom equals method there. From the GridPosition starter class:

class GridPosition {

    final int x;

    final int y;

    GridPosition(final int x, final int y) {
        this.x = x;
        this.y = y;
    }

    /*
     * This equals method is of deliberately narrow scope (only allows comparison with another GridPosition) to increase
     * readability. In general, one should provide a full implementation of Object.equals(Object obj) and a
     * corresponding implementation of Object.hashCode(). See
     *
     * https://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#equals(java.lang.Object)
     *
     * and
     *
     * https://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#hashCode()
     *
     * for more information.
     */
    boolean equals(final GridPosition gridPosition) {
        return this.x == gridPosition.x && this.y == gridPosition.y;
    }

}

We could instead provide a full equals implementation, just need to be wary of the fact that it'll be visible to implementors.

So then is the assertEquals method using the generic equals method from java.lang.Object? @stkent

Yep, exactly, hence the failures!

My vote would be for an overridden equals, the class only exists to track the position

Sorry, that's my bad for not checking throroughly enough when creating the issue! I did check that the change worked locally, but only for some of the tests when the grid position didn't actually change.

I agree, I think overriding equals would be the best plan :) Would you be happy doing that as part of this PR @matthewstyler? You absolutely don't have to, I'm happy to open a separate PR for it :)

ya, no problem @FridaTveit

Thanks for taking the time to do all this @matthewstyler I think it looks good now