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.kafka.common.internals;
  
  import org.apache.kafka.common.errors.InvalidTopicException;
  import org.apache.kafka.test.TestUtils;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  public class TopicTest {
  
      @Test
      public void shouldAcceptValidTopicNames() {
          String maxLengthString = TestUtils.randomString(249);
          String[] validTopicNames = {"valid", "TOPIC", "nAmEs", "ar6", "VaL1d", "_0-9_.", "...", maxLengthString};
  
          for (String topicName : validTopicNames) {
              Topic.validate(topicName);
          }
      }
  
      @Test
      public void shouldThrowOnInvalidTopicNames() {
          char[] longString = new char[250];
          Arrays.fill(longString, 'a');
          String[] invalidTopicNames = {"", "foo bar", "..", "foo:bar", "foo=bar", ".", new String(longString)};
  
          for (String topicName : invalidTopicNames) {
              try {
                  Topic.validate(topicName);
                  fail("No exception was thrown for topic with invalid name: " + topicName);
              } catch (InvalidTopicException e) {
                  // Good
              }
          }
      }
  
      @Test
      public void shouldRecognizeInvalidCharactersInTopicNames() {
          char[] invalidChars = {'/', '\\', ',', '\u0000', ':', '"', '\'', ';', '*', '?', ' ', '\t', '\r', '\n', '='};
  
          for (char c : invalidChars) {
              String topicName = "Is " + c + "illegal";
              assertFalse(Topic.containsValidPattern(topicName));
          }
      }
  
      @Test
      public void testTopicHasCollisionChars() {
          List<String> falseTopics = Arrays.asList("start", "end", "middle", "many");
          List<String> trueTopics = Arrays.asList(
                  ".start", "end.", "mid.dle", ".ma.ny.",
                  "_start", "end_", "mid_dle", "_ma_ny."
          );
  
          for (String topic : falseTopics)
              assertFalse(Topic.hasCollisionChars(topic));
  
          for (String topic : trueTopics)
              assertTrue(Topic.hasCollisionChars(topic));
      }
  
      @Test
      public void testUnifyCollisionChars() {
          assertEquals("topic", Topic.unifyCollisionChars("topic"));
          assertEquals("_topic", Topic.unifyCollisionChars(".topic"));
          assertEquals("_topic", Topic.unifyCollisionChars("_topic"));
          assertEquals("__topic", Topic.unifyCollisionChars("_.topic"));
      }
  
      @Test
      public void testTopicHasCollision() {
          List<String> periodFirstMiddleLastNone = Arrays.asList(".topic", "to.pic", "topic.", "topic");
          List<String> underscoreFirstMiddleLastNone = Arrays.asList("_topic", "to_pic", "topic_", "topic");
  
          // Self
          for (String topic : periodFirstMiddleLastNone)
              assertTrue(Topic.hasCollision(topic, topic));
  
          for (String topic : underscoreFirstMiddleLastNone)
              assertTrue(Topic.hasCollision(topic, topic));
  
          // Same Position
          for (int i = 0; i < periodFirstMiddleLastNone.size(); ++i)
              assertTrue(Topic.hasCollision(periodFirstMiddleLastNone.get(i), underscoreFirstMiddleLastNone.get(i)));
  
          // Different Position
          Collections.reverse(underscoreFirstMiddleLastNone);
          for (int i = 0; i < periodFirstMiddleLastNone.size(); ++i)
              assertFalse(Topic.hasCollision(periodFirstMiddleLastNone.get(i), underscoreFirstMiddleLastNone.get(i)));
      }
  }
  