Assert that two colors are similar using XCTest

XCTAssertColor.swift

    func XCTAssertColor(_ l: UIColor?, _ r: UIColor, accuracy: CGFloat, file: StaticString = #file, line: UInt = #line) {

        guard let l = l else {
            XCTFail("Color is 'nil'", file: file, line: line)
            return
        }

        var (lh, rh) = (CGFloat(0), CGFloat(0))
        var (lb, rb) = (CGFloat(0), CGFloat(0))
        var (ls, rs) = (CGFloat(0), CGFloat(0))
        var (la, ra) = (CGFloat(0), CGFloat(0))

        l.getHue(&lh, saturation: &ls, brightness: &lb, alpha: &la)
        r.getHue(&rh, saturation: &rs, brightness: &rb, alpha: &ra)

        XCTAssertEqual(lh, rh, accuracy: accuracy, "Hue",        file: file, line: line)
        XCTAssertEqual(ls, rs, accuracy: accuracy, "Saturation", file: file, line: line)
        XCTAssertEqual(lb, rb, accuracy: accuracy, "Brightness", file: file, line: line)
        XCTAssertEqual(la, ra, accuracy: accuracy, "Alpha",      file: file, line: line)

    }

XCTAssertColor(#colorLiteral(red: 1, green: 0, blue: 0.6037723036, alpha: 1),  #colorLiteral(red: 1, green: 0.4980392157, blue: 0, alpha: 1), accuracy: 0.001)
XCTAssertColor(#colorLiteral(red: 1, green: 0, blue: 0.6047723036, alpha: 1),  #colorLiteral(red: 1, green: 0, blue: 0.6037723036, alpha: 1), accuracy: 0.001)