### Question:
Rotation extends AAngularMeasure implements IRotation { public static Rotation zero() { return ZERO_ROTATION; } private  Rotation(); private  Rotation(double rad); static Rotation zero(); static Rotation ofRad(double rad); static Rotation ofDeg(double deg); static Rotation ofRotation(double turns); static Rotation ofVec(IVector2 vector); static Rotation ofAngularMeasure(IAngularMeasure angularMeasure); @Override IRotation add(final IAngularMeasure angle); @Override IRotation add(final double angle); @Override IRotation subtract(final IAngularMeasure angle); @Override IRotation subtract(final double angle); @Override IRotation multiply(final double factor);  }### Answer:
@Test public void zero() { assertEquals(0, Rotation.zero().asRad(), ACCURACY); }