### Question:
DistanceCalcEarth implements DistanceCalc { public double calcCircumference(double lat) { return 2 * PI * R * cos(toRadians(lat)); }  @Override double calcDist(double fromLat, double fromLon, double toLat, double toLon); @Override double calcDenormalizedDist(double normedDist); @Override double calcNormalizedDist(double dist); @Override double calcNormalizedDist(double fromLat, double fromLon, double toLat, double toLon); double calcCircumference(double lat); boolean isDateLineCrossOver(double lon1, double lon2); @Override BBox createBBox(double lat, double lon, double radiusInMeter); @Override double calcNormalizedEdgeDistance(double r_lat_deg, double r_lon_deg,
                                             double a_lat_deg, double a_lon_deg,
                                             double b_lat_deg, double b_lon_deg); double calcNormalizedEdgeDistanceNew(double r_lat_deg, double r_lon_deg,
                                                double a_lat_deg, double a_lon_deg,
                                                double b_lat_deg, double b_lon_deg, boolean reduceToSegment); @Override GHPoint calcCrossingPointToEdge(double r_lat_deg, double r_lon_deg,
                                           double a_lat_deg, double a_lon_deg,
                                           double b_lat_deg, double b_lon_deg); @Override boolean validEdgeDistance(double r_lat_deg, double r_lon_deg,
                                     double a_lat_deg, double a_lon_deg,
                                     double b_lat_deg, double b_lon_deg); @Override GHPoint projectCoordinate(double latInDeg, double lonInDeg, double distanceInMeter, double headingClockwiseFromNorth); @Override boolean isCrossBoundary(double lon1, double lon2); @Override String toString(); final static double R; final static double R_EQ; final static double C; final static double KM_MILE; }### Answer:
@Test public void testCalcCircumference() { assertEquals(DistanceCalcEarth.C, dc.calcCircumference(0), 1e-7); }