java-topology/test/jdk/java/io/Reader/NullReader.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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import java.io.Reader;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.CharBuffer;
import java.nio.ReadOnlyBufferException;

import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

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

/*
 * @test
 * @bug 8196298 8204930
 * @run junit NullReader
 * @summary Check for expected behavior of Reader.nullReader().
 */
public class NullReader {
    private static Reader openReader;
    private static Reader closedReader;

    @BeforeAll
    public static void setup() throws IOException {
        openReader = Reader.nullReader();
        closedReader = Reader.nullReader();
        closedReader.close();
    }

    @AfterAll
    public static void closeStream() throws IOException {
        openReader.close();
    }

    @Test
    public void testOpen() {
        assertNotNull(openReader, "Reader.nullReader() returned null");
    }

    @Test
    public void testRead() throws IOException {
        assertEquals(-1, openReader.read(), "read() != -1");
    }

    @Test
    public void testReadBII() throws IOException {
        assertEquals(-1, openReader.read(new char[1], 0, 1),
                "read(char[],int,int) != -1");
    }

    @Test
    public void testReadBIILenZero() throws IOException {
        assertEquals(0, openReader.read(new char[1], 0, 0),
                "read(char[],int,int) != 0");
    }

    @Test
    public void testReadCharBuffer() throws IOException {
        CharBuffer charBuffer = CharBuffer.allocate(1);
        assertEquals(-1, openReader.read(charBuffer),
                "read(CharBuffer) != -1");
    }

    @Test
    public void testReadCharBufferZeroRemaining() throws IOException {
        CharBuffer charBuffer = CharBuffer.allocate(0);
        assertEquals(0, openReader.read(charBuffer),
                "read(CharBuffer) != 0");
    }

    @Test
    public void testReady() throws IOException {
        assertFalse(openReader.ready());
    }

    @Test
    public void testSkip() throws IOException {
        assertEquals(0, openReader.skip(1), "skip() != 0");
    }

    @Test
    public void testTransferTo() throws IOException {
        assertEquals(0, openReader.transferTo(new StringWriter(7)),
                "transferTo() != 0");
    }

    @Test
    public void testReadClosed() throws IOException {
        assertThrows(IOException.class, () -> closedReader.read());
    }

    @Test
    public void testReadBIIClosed() throws IOException {
        assertThrows(IOException.class,
                     () -> closedReader.read(new char[1], 0, 1));
    }

    @Test
    public void testReadCharBufferClosed() throws IOException {
        CharBuffer charBuffer = CharBuffer.allocate(0);
        assertThrows(IOException.class, () -> closedReader.read(charBuffer));
    }

    @Test
    public void testReadCharBufferZeroRemainingClosed() throws IOException {
        CharBuffer charBuffer = CharBuffer.allocate(0);
        assertThrows(IOException.class, () -> closedReader.read(charBuffer));
    }

    @Test
    public void testReadyClosed() throws IOException {
        assertThrows(IOException.class, () -> closedReader.ready());
    }

    @Test
    public void testSkipClosed() throws IOException {
        assertThrows(IOException.class, () -> closedReader.skip(1));
    }

    @Test
    public void testTransferToClosed() throws IOException {
        assertThrows(IOException.class,
                     () -> closedReader.transferTo(new StringWriter(7)));
    }
}