def checkCalcForceExertedByXY(self): print("Checking calcForceExertedByX and calcForceExertedByY...") p1 = Planet(1.0, 1.0, 3.0, 4.0, 5.0, "jupiter.gif") p2 = Planet(2.0, 1.0, 3.0, 4.0, 4e11, "jupiter.gif") p3 = Planet(4.0, 5.0, 3.0, 4.0, 5.0, "jupiter.gif") self.checkEquals(p1.calcForceExertedByX(p2), 133.4, "calcForceExertedByX()", 0.01) self.checkEquals(p1.calcForceExertedByX(p3), 4.002e-11, "calcForceExertedByX()", 0.01) self.checkEquals(p1.calcForceExertedByY(p2), 0.0, "calcForceExertedByY()", 0.01) self.checkEquals(p1.calcForceExertedByY(p3), 5.336e-11, "calcForceExertedByY()", 0.01)