Github user kmurra commented on a diff in the pull request:
https://github.com/apache/flink/pull/4746#discussion_r142800611
--- Diff:
flink-libraries/flink-table/src/test/scala/org/apache/flink/table/utils/CheckExpressionsTableSource.scala
---
@@ -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.table.utils
+
+import org.apache.flink.api.java.typeutils.RowTypeInfo
+import org.apache.flink.api.java.{DataSet, ExecutionEnvironment}
+import org.apache.flink.streaming.api.datastream.DataStream
+import
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment
+import org.apache.flink.table.expressions.Expression
+import org.apache.flink.table.sources.{BatchTableSource,
FilterableTableSource, StreamTableSource}
+import org.apache.flink.types.Row
+
+import java.util
+import java.util.Collections
+
+import scala.collection.JavaConverters._
+
+/**
+ * A table source that takes in assertions and applies them when
applyPredicate is called.
+ * Allows for testing that expression push downs are handled properly
+ * @param typeInfo The type info.
+ * @param assertions A set of assertions as a function reference
+ * @param pushedDown Whether this has been pushed down/
+ */
+class CheckExpressionsTableSource(typeInfo: RowTypeInfo,
--- End diff --
I'll look at doing that. It was my initial approach, but when I saw the
potential set of test cases that would impact, I decided to do something more
conservative. Still do-able.
---
