JoinMatcherTest.java

/*
 * Copyright (C) 2014 Francis Galiegue <fgaliegue@gmail.com>
 *
 * 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.github.fge.grappa.matchers.join;

import com.github.fge.grappa.Grappa;
import com.github.fge.grappa.exceptions.GrappaException;
import com.github.fge.grappa.parsers.BaseParser;
import com.github.fge.grappa.rules.Rule;
import com.github.fge.grappa.run.ParseRunner;
import org.testng.annotations.Test;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.fail;

public final class JoinMatcherTest
{
    static class MyParser
        extends BaseParser<Object>
    {
        Rule rule()
        {
            return join(zeroOrMore('a'))
                .using(optional('b').label("foo"))
                .min(0);
        }
    }

    @Test
    public void joinMatcherYellsIfJoiningRuleMatchesEmpty()
    {
        final CharSequence input = "aaaabaaaaxaaa";
        final MyParser parser = Grappa.createParser(MyParser.class);
        final ParseRunner<Object> runner = new ParseRunner<>(parser.rule());
        final String expectedMessage = "joining rule (foo) of a JoinMatcher" +
            " cannot match an empty character sequence!";

        try {
            runner.run(input);
            fail("No exception thrown!!");
        } catch (GrappaException e) {
            assertThat(e).hasMessage(expectedMessage);
        }
    }
}