DATAREDIS-624 - Upgrade to Reactor 3.1.0.BUILD-SNAPSHOT.

Translate `Mono.then` -> `flatMap`, `Mono.flatMap` -> `flatMapMany`.
This still fails as we also need a compatible version of lettuce.

Original pull request: #245.

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

@@ -125,7 +125,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 		StepVerifier.create(listOperations.leftPush(key, value1)).expectNext(1L).verifyComplete();
 		StepVerifier.create(listOperations.leftPush(key, value2)).expectNext(2L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value2)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value2)
 				.expectNext(value1).verifyComplete();
 	}
 
@@ -140,7 +140,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.leftPushAll(key, value1, value2)).expectNext(2L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value2)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value2)
 				.expectNext(value1).verifyComplete();
 	}
 
@@ -170,7 +170,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.leftPush(key, value1, value3)).expectNext(3L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value2)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value2)
 				.expectNext(value3).expectNext(value1).verifyComplete();
 	}
 
@@ -186,7 +186,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 		StepVerifier.create(listOperations.rightPush(key, value1)).expectNext(1L).verifyComplete();
 		StepVerifier.create(listOperations.rightPush(key, value2)).expectNext(2L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value1)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value1)
 				.expectNext(value2).verifyComplete();
 	}
 
@@ -201,7 +201,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.rightPushAll(key, value1, value2)).expectNext(2L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value1)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value1)
 				.expectNext(value2).verifyComplete();
 	}
 
@@ -231,7 +231,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.rightPush(key, value1, value3)).expectNext(3L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value1)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value1)
 				.expectNext(value3).expectNext(value2).verifyComplete();
 	}
 
@@ -248,7 +248,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.set(key, 1, value1)).expectNext(true).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value1)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value1)
 				.expectNext(value1).verifyComplete();
 	}
 
@@ -265,7 +265,7 @@ public class DefaultReactiveListOperationsIntegrationTests<K, V> {
 
 		StepVerifier.create(listOperations.remove(key, 1, value1)).expectNext(1L).verifyComplete();
 
-		StepVerifier.create(listOperations.range(key, 0, -1).flatMap(Flux::fromIterable)).expectNext(value2)
+		StepVerifier.create(listOperations.range(key, 0, -1).flatMapMany(Flux::fromIterable)).expectNext(value2)
 				.verifyComplete();
 	}