android/testSrc/com/android/tools/idea/rendering/IncludeOverlayTest.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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.android.tools.idea.rendering;

import junit.framework.TestCase;

import java.awt.*;
import java.util.*;
import java.util.List;

public class IncludeOverlayTest extends TestCase {
  public void testSubtractRectangles() throws Exception {
    checkSubtract(new Rectangle(0, 0, 100, 80), Collections.<Rectangle>emptyList());

    checkSubtract(new Rectangle(0, 0, 100, 80), Arrays.asList(new Rectangle(50, 50, 20, 20)));

    checkSubtract(new Rectangle(0, 0, 100, 80), Arrays.asList(new Rectangle(50, 50, 20, 20), new Rectangle(90, 90, 10, 10)));

    checkSubtract(new Rectangle(0, 0, 100, 80),
                  Arrays.asList(new Rectangle(50, 50, 20, 20), new Rectangle(90, 90, 10, 10), new Rectangle(0, 0, 10, 10)));

  }

  private static void checkSubtract(Rectangle rectangle, List<Rectangle> holes) {
    Collection<Rectangle> result = IncludeOverlay.subtractRectangles(rectangle, holes);

    // Do some Monte Carlo testing - pick random coordinates and check that if they
    // are within one of the holes then they are not in the result list and vice versa
    Random random = new Random(42L);
    for (int i = 0; i < 1000; i++) {
      int x = random.nextInt(rectangle.width);
      int y = random.nextInt(rectangle.height);

      boolean inHole = false;
      for (Rectangle hole : holes) {
        if (hole.contains(x, y)) {
          inHole = true;
        }
      }

      boolean inResult = false;
      for (Rectangle r : result) {
        if (r.contains(x, y)) {
          inResult = true;
          break;
        }
      }

      if (inHole == inResult) {
        fail("Wrong result at (" + x + "," + y + ") for rectangle=" + rectangle + " and holes=" + holes + " where inHole=inResult=" +
             inResult);
      }
    }
  }
}