From 488591c419265bc3ffa2dc6917ff23a0705ed7b6 Mon Sep 17 00:00:00 2001
From: Mike McCandless <mikemccand@apache.org>
Date: Fri, 4 Mar 2016 16:53:58 -0500
Subject: [PATCH] add randomized test for GeoUtils.circleToBBox

---
 .../document/LatLonPointDistanceQuery.java    |  2 +-
 .../lucene/search/TestLatLonPointQueries.java | 86 ++++++++++++++++++-
 .../apache/lucene/spatial/util/GeoRect.java   |  5 ++
 3 files changed, 91 insertions(+), 2 deletions(-)

diff --git a/lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointDistanceQuery.java b/lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointDistanceQuery.java
index 7ac21b35c42..9374b17db4e 100644
--- a/lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointDistanceQuery.java
+++ b/lucene/sandbox/src/java/org/apache/lucene/document/LatLonPointDistanceQuery.java
@@ -70,7 +70,7 @@ final class LatLonPointDistanceQuery extends Query {
     final GeoRect box2;
 
     // crosses dateline: split
-    if (box.maxLon < box.minLon) {
+    if (box.crossesDateline()) {
       box1 = new GeoRect(-180.0, box.maxLon, box.minLat, box.maxLat);
       box2 = new GeoRect(box.minLon, 180.0, box.minLat, box.maxLat);
     } else {
diff --git a/lucene/sandbox/src/test/org/apache/lucene/search/TestLatLonPointQueries.java b/lucene/sandbox/src/test/org/apache/lucene/search/TestLatLonPointQueries.java
index 9f9bba2c236..028d6b84476 100644
--- a/lucene/sandbox/src/test/org/apache/lucene/search/TestLatLonPointQueries.java
+++ b/lucene/sandbox/src/test/org/apache/lucene/search/TestLatLonPointQueries.java
@@ -16,11 +16,12 @@
  */
 package org.apache.lucene.search;
 
-import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.document.Document;
+import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.spatial.util.BaseGeoPointTestCase;
 import org.apache.lucene.spatial.util.GeoDistanceUtils;
 import org.apache.lucene.spatial.util.GeoRect;
+import org.apache.lucene.spatial.util.GeoUtils;
 
 public class TestLatLonPointQueries extends BaseGeoPointTestCase {
   // TODO: remove this!
@@ -146,4 +147,87 @@ public class TestLatLonPointQueries extends BaseGeoPointTestCase {
     final double d = GeoDistanceUtils.haversin(centerLat, centerLon, pointLat, pointLon);
     return d >= minRadiusMeters && d <= radiusMeters;
   }
+
+  /** Returns random double min to max or up to 1% outside of that range */
+  private double randomRangeMaybeSlightlyOutside(double min, double max) {
+    return min + (random().nextDouble() + (0.5 - random().nextDouble()) * .02) * (max - min);
+  }
+
+  // We rely heavily on GeoUtils.circleToBBox so we test it here:
+  public void testRandomCircleToBBox() throws Exception {
+    int iters = atLeast(1000);
+    for(int iter=0;iter<iters;iter++) {
+
+      boolean useSmallRanges = random().nextBoolean();
+
+      double radiusMeters;
+
+      double centerLat = randomLat(useSmallRanges);
+      double centerLon = randomLon(useSmallRanges);
+
+      if (useSmallRanges) {
+        // Approx 4 degrees lon at the equator:
+        radiusMeters = random().nextDouble() * 444000;
+      } else {
+        radiusMeters = random().nextDouble() * 50000000;
+      }
+
+      // TODO: randomly quantize radius too, to provoke exact math errors?
+
+      GeoRect bbox = GeoUtils.circleToBBox(centerLon, centerLat, radiusMeters);
+
+      int numPointsToTry = 1000;
+      for(int i=0;i<numPointsToTry;i++) {
+
+        double lat;
+        double lon;
+
+        if (random().nextBoolean()) {
+          lat = randomLat(useSmallRanges);
+          lon = randomLon(useSmallRanges);
+        } else {
+          // pick a lat/lon within the bbox or "slightly" outside it to try to improve test efficiency
+          lat = quantizeLat(GeoUtils.normalizeLat(randomRangeMaybeSlightlyOutside(bbox.minLat, bbox.maxLat)));
+          if (bbox.crossesDateline()) {
+            if (random().nextBoolean()) {
+              lon = quantizeLon(GeoUtils.normalizeLon(randomRangeMaybeSlightlyOutside(bbox.maxLon, -180)));
+            } else {
+              lon = quantizeLon(GeoUtils.normalizeLon(randomRangeMaybeSlightlyOutside(0, bbox.minLon)));
+            }
+          } else {
+            lon = quantizeLon(GeoUtils.normalizeLon(randomRangeMaybeSlightlyOutside(bbox.minLon, bbox.maxLon)));
+          }
+        }
+
+        double distanceMeters = GeoDistanceUtils.haversin(centerLat, centerLon, lat, lon);
+
+        // Haversin says it's within the circle:
+        boolean haversinSays = distanceMeters <= radiusMeters;
+
+        // BBox says its within the box:
+        boolean bboxSays;
+        if (bbox.crossesDateline()) {
+          if (lat >= bbox.minLat && lat <= bbox.maxLat) {
+            bboxSays = lon <= bbox.maxLon || lon >= bbox.minLon;
+          } else {
+            bboxSays = false;
+          }
+        } else {
+          bboxSays = lat >= bbox.minLat && lat <= bbox.maxLat && lon >= bbox.minLon && lon <= bbox.maxLon;
+        }
+
+        if (haversinSays) {
+          if (bboxSays == false) {
+            System.out.println("small=" + useSmallRanges + " centerLat=" + centerLat + " cetnerLon=" + centerLon + " radiusMeters=" + radiusMeters);
+            System.out.println("  bbox: lat=" + bbox.minLat + " to " + bbox.maxLat + " lon=" + bbox.minLon + " to " + bbox.maxLon);
+            System.out.println("  point: lat=" + lat + " lon=" + lon);
+            System.out.println("  haversin: " + distanceMeters);
+            fail("point was within the distance according to haversin, but the bbox doesn't contain it");
+          }
+        } else {
+          // it's fine if haversin said it was outside the radius and bbox said it was inside the box
+        }
+      }
+    }
+  }
 }
diff --git a/lucene/spatial/src/java/org/apache/lucene/spatial/util/GeoRect.java b/lucene/spatial/src/java/org/apache/lucene/spatial/util/GeoRect.java
index 68a450c09fb..e147351b2ca 100644
--- a/lucene/spatial/src/java/org/apache/lucene/spatial/util/GeoRect.java
+++ b/lucene/spatial/src/java/org/apache/lucene/spatial/util/GeoRect.java
@@ -70,4 +70,9 @@ public class GeoRect {
 
     return b.toString();
   }
+
+  /** Returns true if this bounding box crosses the dateline */
+  public boolean crossesDateline() {
+    return maxLon < minLon;
+  }
 }