trunk/core/src/test/java/org/apache/commons/vfs2/test/ProviderRandomSetLengthTests.java

/*
 * 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
 *
 *      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 org.apache.commons.vfs2.test;

import java.io.IOException;

import org.apache.commons.vfs2.Capability;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.RandomAccessContent;
import org.apache.commons.vfs2.Selectors;
import org.apache.commons.vfs2.util.RandomAccessMode;
import org.junit.Assert;

/**
 * Random set length test cases for file providers.
 *
 * @version $Id$
 */
public class ProviderRandomSetLengthTests extends AbstractProviderTestCase
{
    private static final String TEST_DATA = "This is a test file.";

    /**
     * Sets up a scratch folder for the test to use.
     */
    protected FileObject createScratchFolder() throws Exception
    {
        final FileObject scratchFolder = this.getWriteFolder();

        // Make sure the test folder is empty
        scratchFolder.delete(Selectors.EXCLUDE_SELF);
        scratchFolder.createFolder();

        return scratchFolder;
    }

    /**
     * Returns the capabilities required by the tests of this test case.
     */
    @Override
    protected Capability[] getRequiredCaps()
    {
        return new Capability[]
        {
                Capability.GET_TYPE,
                Capability.RANDOM_ACCESS_READ,
                Capability.RANDOM_ACCESS_WRITE,
                Capability.RANDOM_ACCESS_SET_LENGTH };
    }

    /**
     * Writes a file
     */
    public void testRandomSetLength() throws Exception
    {
        FileObject file = null;
        try
        {
            file = this.createScratchFolder().resolveFile("random_write.txt");
            file.createFile();
            final RandomAccessContent ra = file.getContent().getRandomAccessContent(RandomAccessMode.READWRITE);

            // Write long string
            ra.writeBytes(TEST_DATA);
            Assert.assertEquals(TEST_DATA.length(), ra.length());

            // Shrink to length 1
            ra.setLength(1);
            Assert.assertEquals(1, ra.length());
            // now read 1
            ra.seek(0);
            Assert.assertEquals(ra.readByte(), TEST_DATA.charAt(0));

            try
            {
                ra.readByte();
                Assert.fail("Expected " + Exception.class.getName());
            } catch (final IOException e)
            {
                // Expected
            }

            // Grow to length 2
            ra.setLength(2);
            Assert.assertEquals(2, ra.length());
            // We have an undefined extra byte
            ra.seek(1);
            ra.readByte();

        } finally
        {
            if (file != null)
            {
                file.close();
            }
        }
    }
}