src/test/java/org/apache/commons/csv/issues/JiraCsv247Test.java

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 * 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
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
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package org.apache.commons.csv.issues;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.Reader;
import java.io.StringReader;
import java.util.Arrays;
import java.util.Iterator;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
import org.junit.jupiter.api.Test;

class JiraCsv247Test {

    @Test
    void testHeadersMissingOneColumnWhenAllowingMissingColumnNames() throws Exception {
        final CSVFormat format = CSVFormat.DEFAULT.builder().setHeader().setAllowMissingColumnNames(true).get();

        assertTrue(format.getAllowMissingColumnNames(), "We should allow missing column names");

        final Reader in = new StringReader("a,,c,d,e\n1,2,3,4,5\nv,w,x,y,z");
        try (CSVParser parser = format.parse(in)) {
            assertEquals(Arrays.asList("a", "", "c", "d", "e"), parser.getHeaderNames());
            final Iterator<CSVRecord> iterator = parser.iterator();
            CSVRecord record = iterator.next();
            assertEquals("1", record.get(0));
            assertEquals("2", record.get(1));
            assertEquals("3", record.get(2));
            assertEquals("4", record.get(3));
            assertEquals("5", record.get(4));
            record = iterator.next();
            assertEquals("v", record.get(0));
            assertEquals("w", record.get(1));
            assertEquals("x", record.get(2));
            assertEquals("y", record.get(3));
            assertEquals("z", record.get(4));
            assertFalse(iterator.hasNext());
        }
    }

    @Test
    void testHeadersMissingThrowsWhenNotAllowingMissingColumnNames() {
        final CSVFormat format = CSVFormat.DEFAULT.builder().setHeader().get();

        assertFalse(format.getAllowMissingColumnNames(), "By default we should not allow missing column names");

        assertThrows(IllegalArgumentException.class, () -> {
            try (Reader reader = new StringReader("a,,c,d,e\n1,2,3,4,5\nv,w,x,y,z");
                CSVParser parser = format.parse(reader);) {
                // should fail
            }
        }, "1 missing column header is not allowed");

        assertThrows(IllegalArgumentException.class, () -> {
            try (Reader reader = new StringReader("a,,c,d,\n1,2,3,4,5\nv,w,x,y,z");
                CSVParser parser = format.parse(reader);) {
                // should fail
            }
        }, "2+ missing column headers is not allowed!");
    }
}