Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/4851#discussion_r145877337
--- Diff:
flink-streaming-java/src/test/java/org/apache/flink/streaming/runtime/tasks/AcknowledgeStreamMockEnvironment.java
---
@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.streaming.runtime.tasks;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.core.testutils.OneShotLatch;
+import org.apache.flink.runtime.checkpoint.CheckpointMetrics;
+import org.apache.flink.runtime.checkpoint.TaskStateSnapshot;
+import org.apache.flink.runtime.operators.testutils.MockInputSplitProvider;
+
+/**
+ * Stream environment that allows to wait for checkpoint acknowledgement.
+ */
+class AcknowledgeStreamMockEnvironment extends StreamMockEnvironment {
--- End diff --
I did a similar refactoring in one of my pending PRs, but it's ok because
that one will probably not make it into 1.4. What I would still suggest, if you
search for subclasses of `StreamMockEnvironment`, there are still more cases
(some as anonymous classes) that could be replaced by a proper dummy like this.
---
