Mayweather vs Pacquiao, will this bout ever happen?

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It was supposed to be Pacquiao vs Mayweather in Manny's last fight.. but things didn't push through because of drug testing problems if I'm not mistaken. Now that Pacquiao is agreeing to the tests, Mayweather announces he's resting for while, two years I think. So there will likely be no Mayweather-Pacquiao fight anytime soon and with Manny's mom urging him to retire. Will a fight between these two fighters ever happen?