clients/src/test/java/org/apache/kafka/common/internals/TopicTest.java

/*
 * 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.Test;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.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 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)));
    }
}