### Question:
SRTMProvider implements ElevationProvider { String getFileString(double lat, double lon) { int intKey = calcIntKey(lat, lon); String str = areas.get(intKey); if (str == null) return null; int minLat = Math.abs(down(lat)); int minLon = Math.abs(down(lon)); str += "/"; if (lat >= 0) str += "N"; else str += "S"; if (minLat < 10) str += "0"; str += minLat; if (lon >= 0) str += "E"; else str += "W"; if (minLon < 10) str += "0"; if (minLon < 100) str += "0"; str += minLon; return str; } SRTMProvider(); static void main(String[] args); @Override void setCalcMean(boolean calcMean); void setDownloader(Downloader downloader); @Override ElevationProvider setCacheDir(File cacheDir); @Override ElevationProvider setBaseURL(String baseUrl); @Override ElevationProvider setDAType(DAType daType); @Override double getEle(double lat, double lon); @Override void release(); @Override String toString();  }### Answer:
@Test public void testGetFileString() { assertEquals("Eurasia/N49E011", instance.getFileString(49, 11)); assertEquals("Eurasia/N52W002", instance.getFileString(52.268157, -1.230469)); assertEquals("Africa/S06E034", instance.getFileString(-5.965754, 34.804687)); assertEquals("Australia/S29E131", instance.getFileString(-28.304381, 131.484375)); assertEquals("South_America/S09W045", instance.getFileString(-9, -45)); assertEquals("South_America/S10W046", instance.getFileString(-9.1, -45.1)); assertEquals("South_America/S10W045", instance.getFileString(-9.6, -45)); assertEquals("South_America/S28W071", instance.getFileString(-28, -71)); assertEquals("South_America/S29W072", instance.getFileString(-28.88316, -71.070557)); }