### Question:
MercatorProjection { public static double longitudeToPixelX(double longitude, byte zoomLevel) { long mapSize = getMapSize(zoomLevel); return (longitude + 180) / 360 * mapSize; } private  MercatorProjection(); static double calculateGroundResolution(double latitude, byte zoomLevel); static double deltaLat(double deltaPixel, double lat, byte zoom); static long getMapSize(byte zoomLevel); static double latitudeToPixelY(double latitude, byte zoomLevel); static long latitudeToTileY(double latitude, byte zoomLevel); static double longitudeToPixelX(double longitude, byte zoomLevel); static long longitudeToTileX(double longitude, byte zoomLevel); static double pixelXToLongitude(double pixelX, byte zoomLevel); static long pixelXToTileX(double pixelX, byte zoomLevel); static double pixelYToLatitude(double pixelY, byte zoomLevel); static long pixelYToTileY(double pixelY, byte zoomLevel); static double tileXToLongitude(long tileX, byte zoomLevel); static double tileYToLatitude(long tileY, byte zoomLevel); static final double EARTH_CIRCUMFERENCE; static final double LATITUDE_MAX; static final double LATITUDE_MIN; }### Answer:
@Test public void longitudeToPixelXTest() { for (byte zoomLevel = ZOOM_LEVEL_MIN; zoomLevel <= ZOOM_LEVEL_MAX; ++zoomLevel) { double pixelX = MercatorProjection.longitudeToPixelX(CoordinatesUtil.LONGITUDE_MIN, zoomLevel); Assert.assertEquals(0, pixelX, 0); long mapSize = MercatorProjection.getMapSize(zoomLevel); pixelX = MercatorProjection.longitudeToPixelX(0, zoomLevel); Assert.assertEquals(mapSize / 2, pixelX, 0); pixelX = MercatorProjection.longitudeToPixelX(CoordinatesUtil.LONGITUDE_MAX, zoomLevel); Assert.assertEquals(mapSize, pixelX, 0); } }