JetBrainsRuntime/test/jdk/jb/java/io/IoOverNio/FileOutputStreamTest.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/* @test
 * @summary java.io.FileOutputStream uses java.nio.file inside.
 * @library testNio
 * @run junit/othervm
 *      -Djava.nio.file.spi.DefaultFileSystemProvider=testNio.ManglingFileSystemProvider
 *      -Djbr.java.io.use.nio=true
 *      FileOutputStreamTest
 */

import org.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import testNio.ManglingFileSystemProvider;

import java.io.File;
import java.io.FileOutputStream;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.util.Objects;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class FileOutputStreamTest {
    @Rule
    public TemporaryFolder temporaryFolder = new TemporaryFolder();

    @BeforeClass
    public static void checkSystemProperties() {
        Objects.requireNonNull(System.getProperty("java.nio.file.spi.DefaultFileSystemProvider"));
    }

    @Before
    @After
    public void resetFs() {
        ManglingFileSystemProvider.resetTricks();
    }

    @Test
    public void writeSingleByte() throws Exception {
        File file = temporaryFolder.newFile();

        ManglingFileSystemProvider.mangleFileContent = true;
        try (FileOutputStream fos = new FileOutputStream(file)) {
            fos.write('l');
            fos.write('e');
            fos.write('e');
            fos.write('t');
        }

        ManglingFileSystemProvider.mangleFileContent = false;
        assertEquals("1337", Files.readString(file.toPath()));
    }

    @Test
    public void writeByteArray() throws Exception {
        File file = temporaryFolder.newFile();

        ManglingFileSystemProvider.mangleFileContent = true;
        try (FileOutputStream fos = new FileOutputStream(file)) {
            fos.write("hello".getBytes());
        }

        ManglingFileSystemProvider.mangleFileContent = false;
        assertEquals("h3110", Files.readString(file.toPath()));
    }

    @Test
    public void getChannel() throws Exception {
        File file = temporaryFolder.newFile();
        try (FileOutputStream fos = new FileOutputStream(file)) {
            FileChannel channel = fos.getChannel();
            assertTrue(channel.getClass().getName(), channel instanceof testNio.ManglingFileChannel);
        }

    }
}