Ovulation tests can work as preg tests in a pinch??

I just read online that ovulation tests can work as preg tests as well! I'm out of preg tests (I've gotten 3 bfps, and several bfns) and I took an ovulation test this am and a doller store pg test (another double line)and it showed I was ovulating! This isn't possible and I looked online and low and behold, on parent.com many preg ladies have used ovulation tests in addition to preg tests.