DownloadManagerTests.java

/*******************************************************************************
 * Copyright (c) 2012 Pivotal Software, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Pivotal Software, Inc. - initial API and implementation
 *******************************************************************************/
package org.springsource.ide.eclipse.commons.tests;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;

import junit.framework.TestCase;

import org.springsource.ide.eclipse.commons.frameworks.core.downloadmanager.DownloadManager;
import org.springsource.ide.eclipse.commons.frameworks.core.downloadmanager.DownloadManager.DownloadService;
import org.springsource.ide.eclipse.commons.frameworks.core.downloadmanager.DownloadableItem;
import org.springsource.ide.eclipse.commons.frameworks.core.util.IOUtil;

public class DownloadManagerTests extends TestCase {

	public class TestContent {
		public final boolean isError;

		public final String data;

		public TestContent(boolean isError, String data) {
			this.isError = isError;
			this.data = data;
		}
		
		@Override
		public String toString() {
			if (isError) {
				return "Error("+data+")";
			} else {
				return data;
			}
		}
	}

	/**
	 * A test DownloadRequesto it 'accepts' downloaded data when it is equal to
	 * the expected test data and throws an Error otherwise.
	 */
	public class DownloadAcceptor implements DownloadManager.DownloadRequestor {

		private final String expected;

		public String data = null; // Set when data read successfully.

		public DownloadAcceptor(String expect) {
			this.expected = expect;
		}

		public void exec(File downloadedFile) throws Exception {
			String data = getContents(downloadedFile);
			if (data.equals(expected)) {
				this.data = data;
			}
			else {
				throw new Error("Bad data: " + data);
			}
		}

		private String getContents(File downloadedFile) throws IOException {
			FileInputStream input = new FileInputStream(downloadedFile);
			ByteArrayOutputStream data = new ByteArrayOutputStream();
			IOUtil.pipe(input, data);
			return data.toString("utf8");
		}

	}

	/**
	 * A DownloadService who's behavior for specific urls can be 'programmed'.
	 */
	public class TestDownloadService implements DownloadService {
		private final Map<String, LinkedList<TestContent>> responses = new HashMap<String, LinkedList<TestContent>>();
		
		public int fetchCount = 0;

		public void fetch(URL url, OutputStream writeTo) throws IOException {
			fetchCount++;
			LinkedList<TestContent> rs = responses.get(url.toString());
			if (rs == null || rs.isEmpty()) {
				throw new IOException("Not found: " + url);
			}
			TestContent r = rs.removeFirst();
			rs.addLast(r);
			if (r.isError) {
				throw new IOException(r.data);
			} else {
				writeTo.write(r.data.getBytes("utf8"));
			}
		}

		/**
		 * Make this downloadservice return given TestContent for a given url. 
		 * If more then one 'TestContent' element is provided the service will
		 * cycle through them on each download attempt. For example if test content
		 * is 'a', 'b', 'c' then the first download attempt will return 'a', the second
		 * 'b', the third 'c' the fourth 'a' again and so on.
		 */
		public void at(String url, TestContent... content) {
			assertTrue(content.length>0);
			responses.put(url, new LinkedList<TestContent>(Arrays.asList(content)));
		}
	}

	private DownloadManager downloader;

	public void testSimple() throws Exception {
		TestDownloadService service = new TestDownloadService();
		service.at("http://foo", content("Content for http://foo"));
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		File cacheDir = downloader.getCacheDir();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Content for http://foo");
			downloader.doWithDownload(item("foo"), acceptor);
			assertEquals("Content for http://foo", acceptor.data);
		}
		finally {
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			assertEquals(1, service.fetchCount);
		}
	}

	public void testSecondFetchFromCache() throws Exception {
		TestDownloadService service = new TestDownloadService();
		service.at("http://foo", content("Content for http://foo"));
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		File cacheDir = downloader.getCacheDir();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Content for http://foo");
			downloader.doWithDownload(item("foo"), acceptor);
			assertEquals("Content for http://foo", acceptor.data);
			downloader.doWithDownload(item("foo"), acceptor);
		}
		finally {
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			//Twice using same data, but only one fetch!
			assertEquals(1, service.fetchCount);
		}
	}
	
	/**
	 * Check that downloads are retried when download fails with an error.
	 */
	public void testRetryOnError() throws Exception {
		TestDownloadService service = new TestDownloadService();
		service.at("http://foo", error("Foo"), error("Foo"), content("Foo"));
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		File cacheDir = downloader.getCacheDir();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Foo");
			downloader.doWithDownload(item("foo"), acceptor);
			assertEquals("Foo", acceptor.data);
		}
		finally {
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			//Check fetch count. 2 failed attempts + 1 succesful = 3
			assertEquals(3, service.fetchCount);
		}
	}

	/**
	 * Check that downloads are retried when download succeeds but data is
	 * 'corrupted'.
	 */
	public void testRetryOnCorruptedData() throws Exception {
		TestDownloadService service = new TestDownloadService();
		service.at("http://foo", content("CORRUPTED"), content("GARBAGE"), content("Foo"));
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		File cacheDir = downloader.getCacheDir();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Foo");
			downloader.doWithDownload(item("foo"), acceptor);
			assertEquals("Foo", acceptor.data);
		} finally {
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			//Check fetch count. 2 failed attempts + 1 succesfull = 3
			assertEquals(3, service.fetchCount);
		}
	}
	
	/**
	 * Check that setting tries limits the number of tries as expected.
	 */
	public void testRetryCountWithError() throws Exception {
		TestDownloadService service = new TestDownloadService();
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		downloader.setTries(3);
		File cacheDir = downloader.getCacheDir();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Foo");
			downloader.doWithDownload(item("foo"), acceptor);
			fail("Download should have failed");
		} catch (IOException e) {
			assertEquals("Not found: http://foo", e.getMessage());
		} finally {
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			//Check fetch count. 2 failed attempts = 1 try and 2 retries
			assertEquals(3, service.fetchCount);
		}
	}

	public void testRetryInterval() throws Exception {
		TestDownloadService service = new TestDownloadService();
		downloader = new DownloadManager(service, null);
		downloader.allowUIThread(true);
		downloader.setTries(3);
		downloader.setRetryInterval(1000);
		File cacheDir = downloader.getCacheDir();
		long startTime = System.currentTimeMillis();
		try {
			DownloadAcceptor acceptor = new DownloadAcceptor("Foo");
			downloader.doWithDownload(item("foo"), acceptor);
			fail("Download should have failed");
		} catch (IOException e) {
			assertEquals("Not found: http://foo", e.getMessage());
		} finally {
			long duration = System.currentTimeMillis() - startTime;
			//Should expect duration of around 2000 ms as there are 2 retries (and 1 try).
			assertTrue("Duration:"+duration, duration>1500);
			assertTrue("Duration:"+duration, duration<2500);
			downloader.dispose();
			// when cachedir was generated by DownloadManager it should be
			// deleted on dispose.
			assertFalse(cacheDir.exists());
			//Check fetch count. 2 failed attempts = 1 try and 2 retries
			assertEquals(3, service.fetchCount);
		}
		
	}
	
	public TestContent content(String string) {
		return new TestContent(false, string);
	}

	public TestContent error(String msg) {
		return new TestContent(true, msg);
	}

	private DownloadableItem item(final String name) throws MalformedURLException {
		return new DownloadableItem(new URL("http://" + name), downloader) {
			@Override
			protected String getFileName() {
				return name;
			}
		};
	}
}