DATAREDIS-1214 - Fix null return value of GEODIST command.

Original pull request: #565.

Author: christophstrobl

src/main/java/org/springframework/data/redis/connection/jedis/JedisGeoCommands.java

@@ -162,7 +162,8 @@ public Distance geoDist(byte[] key, byte[] member1, byte[] member2) {
 				return null;
 			}
 
-			return distanceConverter.convert(connection.getJedis().geodist(key, member1, member2));
+			Double distance = connection.getJedis().geodist(key, member1, member2);
+			return distance != null ? distanceConverter.convert(distance) : null;
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}
@@ -195,7 +196,8 @@ public Distance geoDist(byte[] key, byte[] member1, byte[] member2, Metric metri
 				return null;
 			}
 
-			return distanceConverter.convert(connection.getJedis().geodist(key, member1, member2, geoUnit));
+			Double distance = connection.getJedis().geodist(key, member1, member2, geoUnit);
+			return distance != null ? distanceConverter.convert(distance) : null;
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceGeoCommands.java

@@ -175,7 +175,9 @@ public Distance geoDist(byte[] key, byte[] member1, byte[] member2, Metric metri
 						distanceConverter));
 				return null;
 			}
-			return distanceConverter.convert(getConnection().geodist(key, member1, member2, geoUnit));
+
+			Double distance = getConnection().geodist(key, member1, member2, geoUnit);
+			return distance != null ? distanceConverter.convert(distance) : null;
 		} catch (Exception ex) {
 			throw convertLettuceAccessException(ex);
 		}

src/test/java/org/springframework/data/redis/connection/AbstractConnectionIntegrationTests.java

@@ -2638,6 +2638,19 @@ public void geoDist() {
 		assertThat(((Distance) result.get(1)).getUnit()).isEqualTo("m");
 	}
 
+	@Test // DATAREDIS-1214
+	@IfProfileValue(name = "redisVersion", value = "3.2+")
+	@WithRedisDriver({ RedisDriver.JEDIS, RedisDriver.LETTUCE })
+	public void geoDistNotExisting() {
+
+		String key = "geo-" + UUID.randomUUID();
+		actual.add(connection.geoAdd(key, Arrays.asList(PALERMO, CATANIA)));
+		actual.add(connection.geoDist(key, "Spring", "Data"));
+
+		List<Object> result = getResults();
+		assertThat(result.get(1)).isNull();
+	}
+
 	@Test // DATAREDIS-438
 	@IfProfileValue(name = "redisVersion", value = "3.2+")
 	@WithRedisDriver({ RedisDriver.JEDIS, RedisDriver.LETTUCE })

src/test/java/org/springframework/data/redis/core/DefaultGeoOperationsTests.java

@@ -186,6 +186,22 @@ public void geoDistShouldReturnDistanceInFeeCorrectly() {
 		assertThat(dist.getUnit()).isEqualTo("ft");
 	}
 
+	@Test // DATAREDIS-1214
+	public void geoDistShouldReturnNullIfNoDistanceCalculable() {
+
+		K key = keyFactory.instance();
+		M member1 = valueFactory.instance();
+		M member2 = valueFactory.instance();
+		M member3 = valueFactory.instance();
+		M member4 = valueFactory.instance();
+
+		geoOperations.add(key, POINT_PALERMO, member1);
+		geoOperations.add(key, POINT_CATANIA, member2);
+
+		Distance dist = geoOperations.distance(key, member3, member4, DistanceUnit.FEET);
+		assertThat(dist).isNull();
+	}
+
 	@Test // DATAREDIS-438, DATAREDIS-614
 	public void testGeoHash() {