        expect(contentRect.width).to.be.equal(70);
        expect(contentRect.height).to.be.equal(30);

        // The target div width is 100, and the tooltip width is 70, and
        // it's centered. The height of the tooltip is 30, and the
        // tooltip is 14px above the target.
        expect(contentRect.left).to.be.equal((100 - 70)/2);
        expect(contentRect.top).to.be.equal(0 - 30 - 14);

        // Also check the math, just in case.
        expect(contentRect.left).to.be.equal((divRect.widt