If you scroll down past the greyscale charts in the link I posted, you'll find the colour ones. I'll quote.
"The final test is the Gretag MacBeth ColorChecker, which tests various hues and is usually one of the hardest tests to perform well in. In this regard, the iPhone 6 once again sets a new record for accuracy. This display is effectively calibrated to sRGB, and one would be hard pressed to find a significant deviation when compared to a reference monitor."