content: /*
   * 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.calcite.test;
  
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.tools.RelBuilder;
  
  import java.util.function.Function;
  
  /**
   * RelOptTestBase is an abstract base for tests which exercise a planner and/or
   * rules via {@link DiffRepository}.
   */
  abstract class RelOptTestBase {
    //~ Methods ----------------------------------------------------------------
  
    /** Creates a fixture for a test. Derived class must override and set
     * {@link RelOptFixture#diffRepos}. */
    RelOptFixture fixture() {
      return RelOptFixture.DEFAULT;
    }
  
    /**
     * Creates a test context with a SQL query.
     * Default catalog: {@link org.apache.calcite.test.catalog.MockCatalogReaderSimple#init()}.
     */
    protected final RelOptFixture sql(String sql) {
      return fixture().sql(sql);
    }
  
    /** Initiates a test case with a given {@link RelNode} supplier. */
    protected final RelOptFixture relFn(Function<RelBuilder, RelNode> relFn) {
      return fixture().relFn(relFn);
    }
  
  }
  