A test used in 19th middle and upper class Black communities to decide of a black American was sufficiently white enough to warrant inclusion. The idea is that your hair should be as straight as a ruler. Today the practice is not rightly condemned as "colorism" but is not altogether abandoned. See also brown paper bag test
"Don't go swimming or you won't be able to pass the ruler test when you meet your date's parent's tonight."
by Bill Peters August 19, 2006