But on the whole the results of that sort of litmus test of friendship are much more positive than negative.

BBC: Breakfast with Frost

And especially in a democratic society, friendship was seen as a test case of whether or not democracy was working.

NPR: Lincoln and Douglass Shared Uncommon Bond

So Douglass especially promoted, championed his interracial friendship as a kind of test case, on-the-ground example of how democracy could work, and in his hope, an inspiration for others in the United States.

NPR: Lincoln and Douglass Shared Uncommon Bond