/*
 * 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, 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.commons.io.input;

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

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import org.apache.commons.io.CharsetsTest;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.function.IOFunction;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import org.junitpioneer.jupiter.DefaultLocale;

/**
 * Tests {@link XmlStreamReader}.
 */
class XmlStreamReaderTest {

    private static final String ISO_8859_1 = StandardCharsets.ISO_8859_1.name();
    private static final String US_ASCII = StandardCharsets.US_ASCII.name();
    private static final String UTF_16 = StandardCharsets.UTF_16.name();
    private static final String UTF_16LE = StandardCharsets.UTF_16LE.name();
    private static final String UTF_16BE = StandardCharsets.UTF_16BE.name();
    private static final String UTF_32 = "UTF-32";
    private static final String UTF_32LE = "UTF-32LE";
    private static final String UTF_32BE = "UTF-32BE";
    private static final String UTF_8 = StandardCharsets.UTF_8.name();

    private static final String XML7 = "xml-prolog-encoding-no-version";
    private static final String XML6 = "xml-prolog-encoding-new-line";
    private static final String XML5 = "xml-prolog-encoding-spaced-single-quotes";
    private static final String XML4 = "xml-prolog-encoding-single-quotes";
    private static final String XML3 = "xml-prolog-encoding-double-quotes";
    private static final String XML2 = "xml-prolog";
    private static final String XML1 = "xml";

    private static final String ENCODING_ATTRIBUTE_XML = "<?xml version=\"1.0\" ?> \n"
            + "<atom:feed xmlns:atom=\"http://www.w3.org/2005/Atom\">\n"
            + "\n"
            + "  <atom:entry>\n"
            + "    <atom:title encoding='base64'><![CDATA\n"
            + "aW5nTGluZSIgLz4";

    private static final int[] NO_BOM_BYTES = {};

    private static final int[] UTF_16BE_BOM_BYTES = {0xFE, 0xFF};

    private static final int[] UTF_16LE_BOM_BYTES = {0xFF, 0XFE};

    private static final int[] UTF_32BE_BOM_BYTES = {0x00, 0x00, 0xFE, 0xFF};

    private static final int[] UTF_32LE_BOM_BYTES = {0xFF, 0XFE, 0x00, 0x00};

    private static final int[] UTF_8_BOM_BYTES = {0xEF, 0xBB, 0xBF};

    private static final Map<String, int[]> BOMs = new HashMap<>();

    static {
        BOMs.put("no-bom", NO_BOM_BYTES);
        BOMs.put("UTF-16BE-bom", UTF_16BE_BOM_BYTES);
        BOMs.put("UTF-16LE-bom", UTF_16LE_BOM_BYTES);
        BOMs.put("UTF-32BE-bom", UTF_32BE_BOM_BYTES);
        BOMs.put("UTF-32LE-bom", UTF_32LE_BOM_BYTES);
        BOMs.put("UTF-16-bom", NO_BOM_BYTES); // it's added by the writer
        BOMs.put("UTF-8-bom", UTF_8_BOM_BYTES);
    }

    private static final MessageFormat XML = new MessageFormat(
            "<root>{2}</root>");

    private static final MessageFormat XML_WITH_PROLOG = new MessageFormat(
            "<?xml version=\"1.0\"?>\n<root>{2}</root>");

    private static final MessageFormat XML_WITH_PROLOG_AND_ENCODING_NEW_LINES = new MessageFormat(
            "<?xml\nversion\n=\n\"1.0\"\nencoding\n=\n\"{1}\"\n?>\n<root>{2}</root>");

    private static final MessageFormat XML_EXTERNAL_PARSED_ENTITY_NO_VERSION = new MessageFormat(
            "<?xml\nencoding\n=\n\"{1}\"\n?>\n<root>{2}</root>");

    private static final MessageFormat XML_WITH_PROLOG_AND_ENCODING_DOUBLE_QUOTES = new MessageFormat(
            "<?xml version=\"1.0\" encoding=\"{1}\"?>\n<root>{2}</root>");

    private static final MessageFormat XML_WITH_PROLOG_AND_ENCODING_SINGLE_QUOTES = new MessageFormat(
            "<?xml version=\"1.0\" encoding=''{1}''?>\n<root>{2}</root>");

    private static final MessageFormat XML_WITH_PROLOG_AND_ENCODING_SPACED_SINGLE_QUOTES = new MessageFormat(
            "<?xml version=\"1.0\" encoding =  \t \n \r''{1}''?>\n<root>{2}</root>");

    private static final MessageFormat INFO = new MessageFormat(
            "\nBOM : {0}\nDoc : {1}\nStream Enc : {2}\nProlog Enc : {3}\n");

    private static final Map<String, MessageFormat> XMLs = new HashMap<>();

    static {
        XMLs.put(XML1, XML);
        XMLs.put(XML2, XML_WITH_PROLOG);
        XMLs.put(XML3, XML_WITH_PROLOG_AND_ENCODING_DOUBLE_QUOTES);
        XMLs.put(XML4, XML_WITH_PROLOG_AND_ENCODING_SINGLE_QUOTES);
        XMLs.put(XML5, XML_WITH_PROLOG_AND_ENCODING_SPACED_SINGLE_QUOTES);
        XMLs.put(XML6, XML_WITH_PROLOG_AND_ENCODING_NEW_LINES);
        XMLs.put(XML7, XML_EXTERNAL_PARSED_ENTITY_NO_VERSION);
    }

    /**
     * Create the XML.
     */
    private String getXML(final String bomType, final String xmlType,
                          final String streamEnc, final String prologEnc) {
        final MessageFormat xml = XMLs.get(xmlType);
        final String info = INFO.format(new Object[]{bomType, xmlType, prologEnc});
        return xml.format(new Object[]{streamEnc, prologEnc, info});
    }

    /**
     * @param bomType   no-bom, UTF-16BE-bom, UTF-16LE-bom, UTF-8-bom
     * @param xmlType   xml, xml-prolog, xml-prolog-charset
     * @param streamEnc encoding of the stream
     * @param prologEnc encoding of the prolog
     * @return XML stream
     * @throws IOException If an I/O error occurs
     */
    protected InputStream getXmlInputStream(final String bomType, final String xmlType,
        final String streamEnc, final String prologEnc) throws IOException {
        final ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);
        int[] bom = BOMs.get(bomType);
        if (bom == null) {
            bom = new int[0];
        }
        for (final int element : bom) {
            baos.write(element);
        }
        try (Writer writer = new OutputStreamWriter(baos, streamEnc)) {
            final String xmlDoc = getXML(bomType, xmlType, streamEnc, prologEnc);
            writer.write(xmlDoc);

            // PADDING TO TEST THINGS WORK BEYOND PUSHBACK_SIZE
            writer.write("<da>\n");
            for (int i = 0; i < 10000; i++) {
                writer.write("<do/>\n");
            }
            writer.write("</da>\n");

        }
        return new ByteArrayInputStream(baos.toByteArray());
    }

    private void parseCharset(final String value, final String charsetName, final IOFunction<InputStream, XmlStreamReader> factory) throws Exception {
        try (InputStream stream = new ByteArrayInputStream(value.getBytes(StandardCharsets.UTF_8))) {
            try (XmlStreamReader xml = factory.apply(stream)) {
                assertEquals(charsetName.toUpperCase(Locale.ROOT), xml.getEncoding(), charsetName);
            }
        }
    }

    void testAlternateDefaultEncoding(final String contentType, final String bomEnc, final String streamEnc, final String prologEnc,
            final String alternateEnc) throws Exception {
        try (InputStream is = getXmlInputStream(bomEnc, prologEnc == null ? XML1 : XML3, streamEnc, prologEnc);
                XmlStreamReader xmlReader = new XmlStreamReader(is, contentType, false, alternateEnc)) {
            testAlternateDefaultEncoding(streamEnc, alternateEnc, xmlReader);
        }
        try (InputStream is = getXmlInputStream(bomEnc, prologEnc == null ? XML1 : XML3, streamEnc, prologEnc);
        // @formatter:off
            XmlStreamReader xmlReader = XmlStreamReader.builder()
                    .setInputStream(is)
                    .setHttpContentType(contentType)
                    .setLenient(false)
                    .setCharset(alternateEnc)
                    .get()) {
            // @formatter:on
            testAlternateDefaultEncoding(streamEnc, alternateEnc, xmlReader);
        }
    }

    private void testAlternateDefaultEncoding(final String streamEnc, final String alternateEnc, final XmlStreamReader xmlReader) {
        assertEquals(xmlReader.getDefaultEncoding(), alternateEnc);
        if (!streamEnc.equals(UTF_16)) {
            // we cannot assert things here because UTF-8, US-ASCII and
            // ISO-8859-1 look alike for the chars used for detection
            // (niallp 2010-10-06 - I re-instated the check below - the tests(6) passed)
            final String enc = alternateEnc != null ? alternateEnc : streamEnc;
            assertEquals(xmlReader.getEncoding(), enc);
        } else {
            // String enc = (alternateEnc != null) ? alternateEnc : streamEnc;
            assertEquals(xmlReader.getEncoding().substring(0, streamEnc.length()), streamEnc);
        }
    }

    @Test
    protected void testConstructorFileInput() throws IOException {
        try (XmlStreamReader reader = new XmlStreamReader(new File("pom.xml"))) {
            // do nothing
        }
        try (XmlStreamReader reader = XmlStreamReader.builder().setFile("pom.xml").get()) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorFileInputNull() {
        assertThrows(NullPointerException.class, () -> new XmlStreamReader((File) null));
    }

    @Test
    protected void testConstructorFileInputOpenOptions() throws IOException {
        try (XmlStreamReader reader = new XmlStreamReader(new File("pom.xml"))) {
            // do nothing
        }
        try (XmlStreamReader reader = XmlStreamReader.builder().setFile("pom.xml").setOpenOptions(StandardOpenOption.READ).get()) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorInputStreamInput() throws IOException {
        final Path path = Paths.get("pom.xml");
        try (XmlStreamReader reader = new XmlStreamReader(Files.newInputStream(path))) {
            // do nothing
        }
        try (@SuppressWarnings("resource")
        XmlStreamReader reader = XmlStreamReader.builder().setInputStream(Files.newInputStream(path)).get()) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorInputStreamInputNull() {
        assertThrows(NullPointerException.class, () -> new XmlStreamReader((InputStream) null));
    }

    @Test
    protected void testConstructorPathInput() throws IOException {
        try (XmlStreamReader reader = new XmlStreamReader(Paths.get("pom.xml"))) {
            // do nothing
        }
        try (XmlStreamReader reader = XmlStreamReader.builder().setPath("pom.xml").get()) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorPathInputNull() {
        assertThrows(NullPointerException.class, () -> new XmlStreamReader((Path) null));
    }

    @Test
    protected void testConstructorURLConnectionInput() throws IOException {
        try (XmlStreamReader reader = new XmlStreamReader(new URL("https://www.apache.org/").openConnection(), UTF_8)) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorURLConnectionInputNull() {
        assertThrows(NullPointerException.class, () -> new XmlStreamReader((URLConnection) null, US_ASCII));
    }

    @Test
    protected void testConstructorURLInput() throws IOException {
        try (XmlStreamReader reader = new XmlStreamReader(new URL("https://www.apache.org/"))) {
            // do nothing
        }
    }

    @Test
    protected void testConstructorURLInputNull() {
        assertThrows(NullPointerException.class, () -> new XmlStreamReader((URL) null));
    }

    // XML Stream generator

    @Test
    void testEncodingAttributeXML() throws Exception {
        try (InputStream is = new ByteArrayInputStream(ENCODING_ATTRIBUTE_XML.getBytes(StandardCharsets.UTF_8));
                XmlStreamReader xmlReader = new XmlStreamReader(is, "", true)) {
            assertEquals(xmlReader.getEncoding(), UTF_8);
        }
        try (InputStream is = new ByteArrayInputStream(ENCODING_ATTRIBUTE_XML.getBytes(StandardCharsets.UTF_8));
                // @formatter:off
                XmlStreamReader xmlReader = XmlStreamReader.builder()
                    .setInputStream(is)
                    .setHttpContentType("")
                    .setLenient(true)
                    .get()) {
            // @formatter:on
            assertEquals(xmlReader.getEncoding(), UTF_8);
        }
    }

    @Test
    void testHttp() throws Exception {
        // niallp 2010-10-06 - remove following 2 tests - I reinstated
        // checks for non-UTF-16 encodings (18 tests) and these failed
        // _testHttpValid("application/xml", "no-bom", "US-ASCII", null);
        // _testHttpValid("application/xml", "UTF-8-bom", "US-ASCII", null);
        testHttpValid("application/xml", "UTF-8-bom", UTF_8, null);
        testHttpValid("application/xml", "UTF-8-bom", UTF_8, UTF_8);
        testHttpValid("application/xml;charset=UTF-8", "UTF-8-bom", UTF_8, null);
        testHttpValid("application/xml;charset=\"UTF-8\"", "UTF-8-bom", UTF_8, null);
        testHttpValid("application/xml;charset='UTF-8'", "UTF-8-bom", UTF_8, null);
        testHttpValid("application/xml;charset=UTF-8", "UTF-8-bom", UTF_8, UTF_8);
        testHttpValid("application/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, null);
        testHttpValid("application/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16);
        testHttpValid("application/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16BE);

        testHttpInvalid("application/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, null);
        testHttpInvalid("application/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16);
        testHttpInvalid("application/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16BE);

        testHttpInvalid("application/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, null);
        testHttpInvalid("application/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32);
        testHttpInvalid("application/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32BE);

        testHttpInvalid("application/xml", "UTF-8-bom", US_ASCII, US_ASCII);
        testHttpInvalid("application/xml;charset=UTF-16", UTF_16LE, UTF_8, UTF_8);
        testHttpInvalid("application/xml;charset=UTF-16", "no-bom", UTF_16BE, UTF_16BE);
        testHttpInvalid("application/xml;charset=UTF-32", UTF_32LE, UTF_8, UTF_8);
        testHttpInvalid("application/xml;charset=UTF-32", "no-bom", UTF_32BE, UTF_32BE);

        testHttpValid("text/xml", "no-bom", US_ASCII, null);
        testHttpValid("text/xml;charset=UTF-8", "UTF-8-bom", UTF_8, UTF_8);
        testHttpValid("text/xml;charset=UTF-8", "UTF-8-bom", UTF_8, null);
        testHttpValid("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, null);
        testHttpValid("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16);
        testHttpValid("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16BE);
        testHttpValid("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, null);
        testHttpValid("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, UTF_32);
        testHttpValid("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, UTF_32BE);
        testHttpValid("text/xml", "UTF-8-bom", US_ASCII, null);

        testAlternateDefaultEncoding("application/xml", "UTF-8-bom", UTF_8, null, null);
        testAlternateDefaultEncoding("application/xml", "no-bom", US_ASCII, null, US_ASCII);
        testAlternateDefaultEncoding("application/xml", "UTF-8-bom", UTF_8, null, UTF_8);
        testAlternateDefaultEncoding("text/xml", "no-bom", US_ASCII, null, null);
        testAlternateDefaultEncoding("text/xml", "no-bom", US_ASCII, null, US_ASCII);
        testAlternateDefaultEncoding("text/xml", "no-bom", US_ASCII, null, UTF_8);

        testHttpInvalid("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, null);
        testHttpInvalid("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16);
        testHttpInvalid("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16BE);
        testHttpInvalid("text/xml;charset=UTF-16", "no-bom", UTF_16BE, UTF_16BE);
        testHttpInvalid("text/xml;charset=UTF-16", "no-bom", UTF_16BE, null);

        testHttpInvalid("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, null);
        testHttpInvalid("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32);
        testHttpInvalid("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32BE);
        testHttpInvalid("text/xml;charset=UTF-32", "no-bom", UTF_32BE, UTF_32BE);
        testHttpInvalid("text/xml;charset=UTF-32", "no-bom", UTF_32BE, null);

        testHttpLenient("text/xml", "no-bom", US_ASCII, null, US_ASCII);
        testHttpLenient("text/xml;charset=UTF-8", "UTF-8-bom", UTF_8, UTF_8, UTF_8);
        testHttpLenient("text/xml;charset=UTF-8", "UTF-8-bom", UTF_8, null, UTF_8);
        testHttpLenient("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, null, UTF_16BE);
        testHttpLenient("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16, UTF_16);
        testHttpLenient("text/xml;charset=UTF-16", "UTF-16BE-bom", UTF_16BE, UTF_16BE, UTF_16BE);
        testHttpLenient("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, null, UTF_32BE);
        testHttpLenient("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, UTF_32, UTF_32);
        testHttpLenient("text/xml;charset=UTF-32", "UTF-32BE-bom", UTF_32BE, UTF_32BE, UTF_32BE);
        testHttpLenient("text/xml", "UTF-8-bom", US_ASCII, null, US_ASCII);

        testHttpLenient("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, null, UTF_16BE);
        testHttpLenient("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16, UTF_16);
        testHttpLenient("text/xml;charset=UTF-16BE", "UTF-16BE-bom", UTF_16BE, UTF_16BE, UTF_16BE);
        testHttpLenient("text/xml;charset=UTF-16", "no-bom", UTF_16BE, UTF_16BE, UTF_16BE);
        testHttpLenient("text/xml;charset=UTF-16", "no-bom", UTF_16BE, null, UTF_16);

        testHttpLenient("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, null, UTF_32BE);
        testHttpLenient("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32, UTF_32);
        testHttpLenient("text/xml;charset=UTF-32BE", "UTF-32BE-bom", UTF_32BE, UTF_32BE, UTF_32BE);
        testHttpLenient("text/xml;charset=UTF-32", "no-bom", UTF_32BE, UTF_32BE, UTF_32BE);
        testHttpLenient("text/xml;charset=UTF-32", "no-bom", UTF_32BE, null, UTF_32);

        testHttpLenient("text/html", "no-bom", US_ASCII, US_ASCII, US_ASCII);
        testHttpLenient("text/html", "no-bom", US_ASCII, null, US_ASCII);
        testHttpLenient("text/html;charset=UTF-8", "no-bom", US_ASCII, UTF_8, UTF_8);
        testHttpLenient("text/html;charset=UTF-16BE", "no-bom", US_ASCII, UTF_8, UTF_8);
        testHttpLenient("text/html;charset=UTF-32BE", "no-bom", US_ASCII, UTF_8, UTF_8);
    }

    @Test
    void testHttpContent() throws Exception {
        final String encoding = UTF_8;
        final String xml = getXML("no-bom", XML3, encoding, encoding);
        try (XmlStreamReader xmlReader = new XmlStreamReader(CharSequenceInputStream.builder().setCharSequence(xml).setCharset(encoding).get())) {
            assertEquals(xmlReader.getEncoding(), encoding, "Check encoding");
            assertEquals(xml, IOUtils.toString(xmlReader), "Check content");
        }
    }

    protected void testHttpInvalid(final String cT, final String bomEnc, final String streamEnc,
        final String prologEnc) throws Exception {
        try (InputStream is = getXmlInputStream(bomEnc, prologEnc == null ? XML2 : XML3, streamEnc, prologEnc)) {
            try {
                new XmlStreamReader(is, cT, false).close();
                fail("It should have failed for HTTP Content-type " + cT + ", BOM " + bomEnc + ", streamEnc " + streamEnc + " and prologEnc " + prologEnc);
            } catch (final IOException ex) {
                assertTrue(ex.getMessage().contains("Illegal encoding,"));
            }
        }
    }

    protected void testHttpLenient(final String cT, final String bomEnc, final String streamEnc,
        final String prologEnc, final String shouldBe) throws Exception {
        try (InputStream is = getXmlInputStream(bomEnc, prologEnc == null ? XML2 : XML3, streamEnc, prologEnc);
            XmlStreamReader xmlReader = new XmlStreamReader(is, cT, true)) {
            assertEquals(xmlReader.getEncoding(), shouldBe);
        }
    }

    void testHttpValid(final String cT, final String bomEnc, final String streamEnc,
        final String prologEnc) throws Exception {
        try (InputStream is = getXmlInputStream(bomEnc, prologEnc == null ? XML1 : XML3, streamEnc, prologEnc);
            XmlStreamReader xmlReader = new XmlStreamReader(is, cT, false)) {
            if (!streamEnc.equals(UTF_16)) {
                // we cannot assert things here because UTF-8, US-ASCII and
                // ISO-8859-1 look alike for the chars used for detection
                // (niallp 2010-10-06 - I re-instated the check below and removed the 2 tests that failed)
                assertEquals(xmlReader.getEncoding(), streamEnc);
            } else {
                assertEquals(xmlReader.getEncoding().substring(0, streamEnc.length()), streamEnc);
            }
        }
    }

    @ParameterizedTest(name = "{0}")
    @MethodSource(CharsetsTest.AVAIL_CHARSETS)
    void testIO_815(final String charsetName) throws Exception {
        final MessageFormat messageFormat = new MessageFormat("<?xml version=\"1.0\" encoding=''{0}''?>\n<root>text</root>");
        final IOFunction<InputStream, XmlStreamReader> factoryCtor = XmlStreamReader::new;
        final IOFunction<InputStream, XmlStreamReader> factoryBuilder = stream -> XmlStreamReader.builder().setInputStream(stream).get();
        parseCharset(messageFormat.format(new Object[] { charsetName }), charsetName, factoryCtor);
        parseCharset(messageFormat.format(new Object[] { charsetName }), charsetName, factoryBuilder);
        for (final String alias : Charset.forName(charsetName).aliases()) {
            parseCharset(messageFormat.format(new Object[] { alias }), alias, factoryCtor);
            parseCharset(messageFormat.format(new Object[] { alias }), alias, factoryBuilder);
        }
    }

    // Turkish language has specific rules to convert dotted and dotless i character.
    @Test
    @DefaultLocale(language = "tr")
    void testLowerCaseEncodingWithTurkishLocale_IO_557() throws Exception {
        final String[] encodings = { "iso8859-1", "us-ascii", "utf-8" }; // lower-case
        for (final String encoding : encodings) {
            final String xml = getXML("no-bom", XML3, encoding, encoding);
            try (ByteArrayInputStream is = new ByteArrayInputStream(xml.getBytes(encoding));
                    XmlStreamReader xmlReader = new XmlStreamReader(is)) {
                assertTrue(encoding.equalsIgnoreCase(xmlReader.getEncoding()), "Check encoding : " + encoding);
                assertEquals(xml, IOUtils.toString(xmlReader), "Check content");
            }
        }
    }

    @SuppressWarnings("resource")
    protected void testRawBomInvalid(final String bomEnc, final String streamEnc,
        final String prologEnc) throws Exception {
        final InputStream is = getXmlInputStream(bomEnc, XML3, streamEnc, prologEnc);
        XmlStreamReader xmlReader = null;
        try {
            xmlReader = XmlStreamReader.builder().setInputStream(is).setLenient(false).get();
            final String foundEnc = xmlReader.getEncoding();
            fail("Expected IOException for BOM " + bomEnc + ", streamEnc " + streamEnc + " and prologEnc " + prologEnc
                + ": found " + foundEnc);
        } catch (final IOException ex) {
            assertTrue(ex.getMessage().contains("Illegal encoding,"));
        }
        if (xmlReader != null) {
            xmlReader.close();
        }
    }

    @Test
    void testRawBomUtf16() throws Exception {
        testRawBomValid(UTF_16BE);
        testRawBomValid(UTF_16LE);
        testRawBomValid(UTF_16);

        testRawBomInvalid("UTF-16BE-bom", UTF_16BE, UTF_16LE);
        testRawBomInvalid("UTF-16LE-bom", UTF_16LE, UTF_16BE);
        testRawBomInvalid("UTF-16LE-bom", UTF_16LE, UTF_8);
    }

    @Test
    void testRawBomUtf32() throws Exception {
        testRawBomValid(UTF_32BE);
        testRawBomValid(UTF_32LE);
        testRawBomValid(UTF_32);

        testRawBomInvalid("UTF-32BE-bom", UTF_32BE, UTF_32LE);
        testRawBomInvalid("UTF-32LE-bom", UTF_32LE, UTF_32BE);
        testRawBomInvalid("UTF-32LE-bom", UTF_32LE, UTF_8);
    }

    @Test
    void testRawBomUtf8() throws Exception {
        testRawBomValid(UTF_8);
        testRawBomInvalid("UTF-8-bom", US_ASCII, US_ASCII);
        testRawBomInvalid("UTF-8-bom", ISO_8859_1, ISO_8859_1);
        testRawBomInvalid("UTF-8-bom", UTF_8, UTF_16);
        testRawBomInvalid("UTF-8-bom", UTF_8, UTF_16BE);
        testRawBomInvalid("UTF-8-bom", UTF_8, UTF_16LE);
        testRawBomInvalid("UTF-16BE-bom", UTF_16BE, UTF_16LE);
        testRawBomInvalid("UTF-16LE-bom", UTF_16LE, UTF_16BE);
        testRawBomInvalid("UTF-16LE-bom", UTF_16LE, UTF_8);
        testRawBomInvalid("UTF-32BE-bom", UTF_32BE, UTF_32LE);
        testRawBomInvalid("UTF-32LE-bom", UTF_32LE, UTF_32BE);
        testRawBomInvalid("UTF-32LE-bom", UTF_32LE, UTF_8);
    }

    protected void testRawBomValid(final String encoding) throws Exception {
        try (InputStream is = getXmlInputStream(encoding + "-bom", XML3, encoding, encoding);
            XmlStreamReader xmlReader = new XmlStreamReader(is, false)) {
            if (!encoding.equals(UTF_16) && !encoding.equals(UTF_32)) {
                assertEquals(xmlReader.getEncoding(), encoding);
            } else {
                assertEquals(xmlReader.getEncoding().substring(0, encoding.length()), encoding);
            }
        }
    }

    @Test
    void testRawContent() throws Exception {
        final String encoding = UTF_8;
        final String xml = getXML("no-bom", XML3, encoding, encoding);
        try (XmlStreamReader xmlReader = new XmlStreamReader(CharSequenceInputStream.builder().setCharSequence(xml).setCharset(encoding).get())) {
            assertEquals(xmlReader.getEncoding(), encoding, "Check encoding");
            assertEquals(xml, IOUtils.toString(xmlReader), "Check content");
        }
    }

    @Test
    void testRawNoBomCp1047() throws Exception {
        testRawNoBomValid("CP1047");
    }

    protected void testRawNoBomInvalid(final String encoding) throws Exception {
        try (InputStream is = getXmlInputStream("no-bom", XML3, encoding, encoding)) {
            final XmlStreamReader xmlStreamReader = new XmlStreamReader(is, false);
            final IOException ex = assertThrows(IOException.class, xmlStreamReader::close);
            assertTrue(ex.getMessage().contains("Invalid encoding,"));
        }
    }

    @Test
    void testRawNoBomIso8859_1() throws Exception {
        testRawNoBomValid(ISO_8859_1);
    }

    @Test
    void testRawNoBomUsAscii() throws Exception {
        testRawNoBomValid(US_ASCII);
    }

    @Test
    void testRawNoBomUtf16BE() throws Exception {
        testRawNoBomValid(UTF_16BE);
    }

    @Test
    void testRawNoBomUtf16LE() throws Exception {
        testRawNoBomValid(UTF_16LE);
    }

    @Test
    void testRawNoBomUtf32BE() throws Exception {
        testRawNoBomValid(UTF_32BE);
    }

    @Test
    void testRawNoBomUtf32LE() throws Exception {
        testRawNoBomValid(UTF_32LE);
    }

    @Test
    void testRawNoBomUtf8() throws Exception {
        testRawNoBomValid(UTF_8);
    }

    protected void testRawNoBomValid(final String encoding) throws Exception {
        InputStream is = getXmlInputStream("no-bom", XML1, encoding, encoding);
        XmlStreamReader xmlReader = new XmlStreamReader(is, false);
        assertEquals(xmlReader.getEncoding(), UTF_8);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML2, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), UTF_8);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML3, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), encoding);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML4, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), encoding);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML5, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), encoding);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML6, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), encoding);
        xmlReader.close();

        is = getXmlInputStream("no-bom", XML7, encoding, encoding);
        xmlReader = new XmlStreamReader(is);
        assertEquals(xmlReader.getEncoding(), encoding);
        xmlReader.close();
}
}
