/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed 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.io.output;

import junit.framework.TestCase;
//import org.apache.commons.fileupload.DeferredFileOutputStream;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Arrays;

/**
 * Unit tests for the DeferredFileOutputStream class.
 *
 * @author Martin Cooper
 *
 * @version $Id: DeferredFileOutputStreamTest.java,v 1.2 2004/02/23 05:02:25 bayard Exp $
 */
public class DeferredFileOutputStreamTest extends TestCase
 {

    /**
     * The test data as a string (which is the simplest form).
     */
    private String testString = "0123456789";

    /**
     * The test data as a byte array, derived from the string.
     */
    private byte[] testBytes = testString.getBytes();

    /**
     * Standard JUnit test case constructor.
     *
     * @param name The name of the test case.
     */
    public DeferredFileOutputStreamTest(String name)
    {
        super(name);
    }

    /**
     * Tests the case where the amount of data falls below the threshold, and
     * is therefore confined to memory.
     */
    public void testBelowThreshold()
    {
        DeferredFileOutputStream dfos =
                new DeferredFileOutputStream(testBytes.length + 42, null);
        try
        {
            dfos.write(testBytes, 0, testBytes.length);
            dfos.close();
        }
        catch (IOException e) {
            fail("Unexpected IOException");
        }
        assertTrue(dfos.isInMemory());

        byte[] resultBytes = dfos.getData();
        assertTrue(resultBytes.length == testBytes.length);
        assertTrue(Arrays.equals(resultBytes, testBytes));
    }

    /**
     * Tests the case where the amount of data is exactly the same as the
     * threshold. The behavior should be the same as that for the amount of
     * data being below (i.e. not exceeding) the threshold.
     */
    public void testAtThreshold() {
        DeferredFileOutputStream dfos =
                new DeferredFileOutputStream(testBytes.length, null);
        try
        {
            dfos.write(testBytes, 0, testBytes.length);
            dfos.close();
        }
        catch (IOException e) {
            fail("Unexpected IOException");
        }
        assertTrue(dfos.isInMemory());

        byte[] resultBytes = dfos.getData();
        assertTrue(resultBytes.length == testBytes.length);
        assertTrue(Arrays.equals(resultBytes, testBytes));
    }

    /**
     * Tests the case where the amount of data exceeds the threshold, and is
     * therefore written to disk. The actual data written to disk is verified,
     * as is the file itself.
     */
    public void testAboveThreshold() {
        File testFile = new File("testAboveThreshold.dat");

        // Ensure that the test starts from a clean base.
        testFile.delete();

        DeferredFileOutputStream dfos =
                new DeferredFileOutputStream(testBytes.length - 5, testFile);
        try
        {
            dfos.write(testBytes, 0, testBytes.length);
            dfos.close();
        }
        catch (IOException e) {
            fail("Unexpected IOException");
        }
        assertFalse(dfos.isInMemory());
        assertNull(dfos.getData());

        verifyResultFile(testFile);

        // Ensure that the test starts from a clean base.
        testFile.delete();
    }

    /**
     * Tests the case where there are multiple writes beyond the threshold, to
     * ensure that the thresholdReached() method is only called
     * once, as the threshold is crossed for the first time.
     */
    public void testThresholdReached() {
        File testFile = new File("testThresholdReached.dat");

        // Ensure that the test starts from a clean base.
        testFile.delete();

        DeferredFileOutputStream dfos =
                new DeferredFileOutputStream(testBytes.length / 2, testFile);
        int chunkSize = testBytes.length / 3;

        try
        {
            dfos.write(testBytes, 0, chunkSize);
            dfos.write(testBytes, chunkSize, chunkSize);
            dfos.write(testBytes, chunkSize * 2,
                    testBytes.length - chunkSize * 2);
            dfos.close();
        }
        catch (IOException e) {
            fail("Unexpected IOException");
        }
        assertFalse(dfos.isInMemory());
        assertNull(dfos.getData());

        verifyResultFile(testFile);

        // Ensure that the test starts from a clean base.
        testFile.delete();
    }

    /**
     * Verifies that the specified file contains the same data as the original
     * test data.
     *
     * @param testFile The file containing the test output.
     */
    private void verifyResultFile(File testFile) {
        try
        {
            FileInputStream fis = new FileInputStream(testFile);
            assertTrue(fis.available() == testBytes.length);

            byte[] resultBytes = new byte[testBytes.length];
            assertTrue(fis.read(resultBytes) == testBytes.length);

            assertTrue(Arrays.equals(resultBytes, testBytes));
            assertTrue(fis.read(resultBytes) == -1);

            try
            {
                fis.close();
            }
            catch (IOException e) {
                // Ignore an exception on close
            }
        }
        catch (FileNotFoundException e) {
            fail("Unexpected FileNotFoundException");
        }
        catch (IOException e) {
            fail("Unexpected IOException");
        }
    }
}