add more tests to geotileutils

Author: talevy

server/src/test/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoTileUtilsTests.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.search.aggregations.bucket.geogrid;
 
 import org.elasticsearch.common.geo.GeoPoint;
+import org.elasticsearch.geometry.Rectangle;
 import org.elasticsearch.test.ESTestCase;
 
 import static org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils.MAX_ZOOM;
@@ -28,8 +29,10 @@
 import static org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils.keyToGeoPoint;
 import static org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils.longEncode;
 import static org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils.stringEncode;
+import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.closeTo;
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
 
 public class GeoTileUtilsTests extends ESTestCase {
 
@@ -231,4 +234,23 @@ public void testSingularityAtPoles() {
         String clippedTileIndex = stringEncode(longEncode(lon, clippedLat, zoom));
         assertEquals(tileIndex, clippedTileIndex);
     }
+
+    public void testPointToTile() {
+        int zoom = randomIntBetween(0, MAX_ZOOM);
+        int tiles = 1 << zoom;
+        int xTile = randomIntBetween(0, zoom);
+        int yTile = randomIntBetween(0, zoom);
+        Rectangle rectangle = GeoTileUtils.toBoundingBox(xTile, yTile, zoom);
+        // check corners
+        assertThat(GeoTileUtils.getXTile(rectangle.getMinX(), tiles), equalTo(xTile));
+        assertThat(GeoTileUtils.getXTile(rectangle.getMaxX(), tiles), equalTo(Math.min(tiles - 1, xTile + 1)));
+        assertThat(GeoTileUtils.getYTile(rectangle.getMaxY(), tiles), anyOf(equalTo(yTile - 1), equalTo(yTile)));
+        assertThat(GeoTileUtils.getYTile(rectangle.getMinY(), tiles), anyOf(equalTo(yTile + 1), equalTo(yTile)));
+        // check point inside
+        double x = randomDoubleBetween(rectangle.getMinX(), rectangle.getMaxX(), false);
+        double y = randomDoubleBetween(rectangle.getMinY(), rectangle.getMaxY(), false);
+        assertThat(GeoTileUtils.getXTile(x, tiles), equalTo(xTile));
+        assertThat(GeoTileUtils.getYTile(y, tiles), equalTo(yTile));
+
+    }
 }