DelegatingVisitorTest.java

/*
 * Copyright 2009 Google Inc.
 *
 * Licensed 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 com.google.common.css.compiler.passes;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.css.compiler.ast.CssSelectorNode;
import com.google.common.css.compiler.ast.CssTreeVisitor;
import com.google.common.css.compiler.ast.DefaultTreeVisitor;
import java.util.ArrayList;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests {@link DelegatingVisitor} */
@RunWith(JUnit4.class)
public class DelegatingVisitorTest {

  @Test
  public void testInvocationOrder() throws Exception {
    List<String> orderRecord = new ArrayList<>();
    DefaultTreeVisitor visitor1 = new RecordingVisitor("visitor1", orderRecord);
    DefaultTreeVisitor visitor2 = new RecordingVisitor("visitor2", orderRecord);

    CssTreeVisitor delegatingVisitor = DelegatingVisitor.from(visitor1, visitor2);

    delegatingVisitor.enterSelector(null /* selector */);
    delegatingVisitor.leaveSelector(null /* selector */);

    assertThat(orderRecord)
        .containsExactly("enter visitor1", "enter visitor2", "leave visitor2", "leave visitor1")
        .inOrder();
  }

  private static class RecordingVisitor extends DefaultTreeVisitor {

    private final String name;
    private final List<String> orderRecord;

    RecordingVisitor(String name, List<String> orderRecord) {
      this.name = name;
      this.orderRecord = orderRecord;
    }

    @Override
    public boolean enterSelector(CssSelectorNode selector) {
      orderRecord.add("enter " + name);
      return super.enterSelector(selector);
    }

    @Override
    public void leaveSelector(CssSelectorNode selector) {
      orderRecord.add("leave " + name);
      super.leaveSelector(selector);
    }
  }
}