### Question:
Force implements Direction, Updatable { public static Force fromVector(double ox, double oy, double x, double y) { final double dh = x - ox; final double dv = y - oy; final double norm; if (dh > dv) { norm = Math.abs(dh); } else { norm = Math.abs(dv); } final double sx; final double sy; if (Double.compare(norm, 0.0) == 0) { sx = 0; sy = 0; } else { sx = dh / norm; sy = dv / norm; } final Force force = new Force(sx, sy); force.setVelocity(norm); return force; } Force();  Force(double fh, double fv);  Force(double fh, double fv, double velocity, double sensibility);  Force(Force force); static Force fromVector(double ox, double oy, double x, double y); void zero(); void setVelocity(double velocity); void setSensibility(double sensibility); void addDirection(double extrp, Direction direction); void addDirection(double extrp, double fh, double fv); void setDirection(Direction direction); void setDirection(double fh, double fv); void setDestination(double fh, double fv); void setDirectionMaximum(Direction max); void setDirectionMinimum(Direction min); double getVelocity(); double getSensibility(); boolean isDecreasingHorizontal(); boolean isIncreasingHorizontal(); @Override void update(double extrp); @Override double getDirectionHorizontal(); @Override double getDirectionVertical(); @Override int hashCode(); @Override boolean equals(Object object); @Override String toString();  }### Answer:
@Test void testFromVector() { assertForce(0.0, 0.0, 0.0, 0.0, Force.fromVector(0.0, 0.0, 0.0, 0.0)); assertForce(0.75, 1.0, 4.0, 0.0, Force.fromVector(0.0, 1.0, 3.0, 5.0)); assertForce(-1.0, -3.0, 1.0, 0.0, Force.fromVector(0.0, 1.0, -1.0, -2.0)); }