Multiple GEORADIUS bugs fixed.

By grepping the continuous integration errors log a number of GEORADIUS
tests failures were detected.

Fortunately when a GEORADIUS failure happens, the test suite logs enough
information in order to reproduce the problem: the PRNG seed,
coordinates and radius of the query.

By reproducing the issues, three different bugs were discovered and
fixed in this commit. This commit also improves the already good
reporting of the fuzzer and adds the failure vectors as regression
tests.

The issues found:

1. We need larger squares around the poles in order to cover the area
requested by the user. There were already checks in order to use a
smaller step (larger squares) but the limit set (+/- 67 degrees) is not
enough in certain edge cases, so 66 is used now.

2. Even near the equator, when the search area center is very near the
edge of the square, the north, south, west or ovest square may not be
able to fully cover the specified radius. Now a test is performed at the
edge of the initial guessed search area, and larger squares are used in
case the test fails.

3. Because of rounding errors between Redis and Tcl, sometimes the test
signaled false positives. This is now addressed.

Whenever possible the original code was improved a bit in other ways. A
debugging example stanza was added in order to make the next debugging
session simpler when the next bug is found.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/geohash.h b/src/geohash.h
index c2f57bed0..ed2ef9336 100644
--- a/src/geohash.h
+++ b/src/geohash.h
@@ -95,7 +95,7 @@ typedef struct {
  * -1:failed
  */
 void geohashGetCoordRange(GeoHashRange *long_range, GeoHashRange *lat_range);
-int geohashEncode(GeoHashRange *long_range, GeoHashRange *lat_range,
+int geohashEncode(const GeoHashRange *long_range, const GeoHashRange *lat_range,
                   double longitude, double latitude, uint8_t step,
                   GeoHashBits *hash);
 int geohashEncodeType(double longitude, double latitude,