/*
* 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 com.twelvemonkeys.util;
import junit.framework.TestCase;
import java.io.*;
/**
* Abstract test class for {@link Object} methods and contracts.
* <p>
* To use, simply extend this class, and implement
* the {@link #makeObject()} method.
* <p>
* If your {@link Object} fails one of these tests by design,
* you may still use this base set of cases. Simply override the
* test case (method) your {@link Object} fails.
*
* @version $Revision: #2 $ $Date: 2008/07/15 $
*
* @author Rodney Waldhoff
* @author Stephen Colebourne
* @author Anonymous
*/
public abstract class ObjectAbstractTestCase extends TestCase {
//-----------------------------------------------------------------------
/**
* Implement this method to return the object to test.
*
* @return the object to test
*/
public abstract Object makeObject();
/**
* Override this method if a subclass is testing an object
* that cannot serialize an "empty" Collection.
* (e.g. Comparators have no contents)
*
* @return true
*/
public boolean supportsEmptyCollections() {
return true;
}
/**
* Override this method if a subclass is testing an object
* that cannot serialize a "full" Collection.
* (e.g. Comparators have no contents)
*
* @return true
*/
public boolean supportsFullCollections() {
return true;
}
/**
* Is serialization testing supported.
* Default is true.
*/
public boolean isTestSerialization() {
return true;
}
/**
* Returns true to indicate that the collection supports equals() comparisons.
* This implementation returns true;
*/
public boolean isEqualsCheckable() {
return true;
}
//-----------------------------------------------------------------------
public void testObjectEqualsSelf() {
Object obj = makeObject();
assertEquals("A Object should equal itself", obj, obj);
}
public void testEqualsNull() {
Object obj = makeObject();
assertEquals(false, obj.equals(null)); // make sure this doesn't throw NPE either
}
public void testObjectHashCodeEqualsSelfHashCode() {
Object obj = makeObject();
assertEquals("hashCode should be repeatable", obj.hashCode(), obj.hashCode());
}
public void testObjectHashCodeEqualsContract() {
Object obj1 = makeObject();
if (obj1.equals(obj1)) {
assertEquals(
"[1] When two objects are equal, their hashCodes should be also.",
obj1.hashCode(), obj1.hashCode());
}
Object obj2 = makeObject();
if (obj1.equals(obj2)) {
assertEquals(
"[2] When two objects are equal, their hashCodes should be also.",
obj1.hashCode(), obj2.hashCode());
assertTrue(
"When obj1.equals(obj2) is true, then obj2.equals(obj1) should also be true",
obj2.equals(obj1));
}
}
public void testSerializeDeserializeThenCompare() throws Exception {
Object obj = makeObject();
if (obj instanceof Serializable && isTestSerialization()) {
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(buffer);
out.writeObject(obj);
out.close();
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(buffer.toByteArray()));
Object dest = in.readObject();
in.close();
if (isEqualsCheckable()) {
assertEquals("obj != deserialize(serialize(obj))", obj, dest);
}
}
}
/**
* Sanity check method, makes sure that any Serializable
* class can be serialized and de-serialized in memory,
* using the handy makeObject() method
*
* @throws java.io.IOException
* @throws ClassNotFoundException
*/
public void testSimpleSerialization() throws Exception {
Object o = makeObject();
if (o instanceof Serializable && isTestSerialization()) {
byte[] objekt = writeExternalFormToBytes((Serializable) o);
Object p = readExternalFormFromBytes(objekt);
}
}
/**
* Tests serialization by comparing against a previously stored version in CVS.
* If the test object is serializable, confirm that a canonical form exists.
*/
public void testCanonicalEmptyCollectionExists() {
if (supportsEmptyCollections() && isTestSerialization() && !skipSerializedCanonicalTests()) {
Object object = makeObject();
if (object instanceof Serializable) {
String name = getCanonicalEmptyCollectionName(object);
assertTrue(
"Canonical empty collection (" + name + ") is not in CVS",
new File(name).exists());
}
}
}
/**
* Tests serialization by comparing against a previously stored version in CVS.
* If the test object is serializable, confirm that a canonical form exists.
*/
public void testCanonicalFullCollectionExists() {
if (supportsFullCollections() && isTestSerialization() && !skipSerializedCanonicalTests()) {
Object object = makeObject();
if (object instanceof Serializable) {
String name = getCanonicalFullCollectionName(object);
assertTrue(
"Canonical full collection (" + name + ") is not in CVS",
new File(name).exists());
}
}
}
// protected implementation
//-----------------------------------------------------------------------
/**
* Get the version of Collections that this object tries to
* maintain serialization compatibility with. Defaults to 1, the
* earliest Collections version. (Note: some collections did not
* even exist in this version).
*
* This constant makes it possible for TestMap (and other subclasses,
* if necessary) to automatically check CVS for a versionX copy of a
* Serialized object, so we can make sure that compatibility is maintained.
* See, for example, TestMap.getCanonicalFullMapName(Map map).
* Subclasses can override this variable, indicating compatibility
* with earlier Collections versions.
*
* @return The version, or {@code null} if this object shouldn't be
* tested for compatibility with previous versions.
*/
public String getCompatibilityVersion() {
return "1";
}
protected String getCanonicalEmptyCollectionName(Object object) {
StringBuilder retval = new StringBuilder();
retval.append("data/test/");
String colName = object.getClass().getName();
colName = colName.substring(colName.lastIndexOf(".") + 1, colName.length());
retval.append(colName);
retval.append(".emptyCollection.version");
retval.append(getCompatibilityVersion());
retval.append(".obj");
return retval.toString();
}
protected String getCanonicalFullCollectionName(Object object) {
StringBuilder retval = new StringBuilder();
retval.append("data/test/");
String colName = object.getClass().getName();
colName = colName.substring(colName.lastIndexOf(".") + 1, colName.length());
retval.append(colName);
retval.append(".fullCollection.version");
retval.append(getCompatibilityVersion());
retval.append(".obj");
return retval.toString();
}
/**
* Write a Serializable or Externalizable object as
* a file at the given path. NOT USEFUL as part
* of a unit test; this is just a utility method
* for creating disk-based objects in CVS that can become
* the basis for compatibility tests using
* readExternalFormFromDisk(String path)
*
* @param o Object to serialize
* @param path path to write the serialized Object
* @exception java.io.IOException
*/
protected void writeExternalFormToDisk(Serializable o, String path) throws IOException {
FileOutputStream fileStream = new FileOutputStream(path);
writeExternalFormToStream(o, fileStream);
}
/**
* Converts a Serializable or Externalizable object to
* bytes. Useful for in-memory tests of serialization
*
* @param o Object to convert to bytes
* @return serialized form of the Object
* @exception java.io.IOException
*/
protected byte[] writeExternalFormToBytes(Serializable o) throws IOException {
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
writeExternalFormToStream(o, byteStream);
return byteStream.toByteArray();
}
/**
* Reads a Serialized or Externalized Object from disk.
* Useful for creating compatibility tests between
* different CVS versions of the same class
*
* @param path path to the serialized Object
* @return the Object at the given path
* @exception java.io.IOException
* @exception ClassNotFoundException
*/
protected Object readExternalFormFromDisk(String path) throws IOException, ClassNotFoundException {
FileInputStream stream = new FileInputStream(path);
return readExternalFormFromStream(stream);
}
/**
* Read a Serialized or Externalized Object from bytes.
* Useful for verifying serialization in memory.
*
* @param b byte array containing a serialized Object
* @return Object contained in the bytes
* @exception java.io.IOException
* @exception ClassNotFoundException
*/
protected Object readExternalFormFromBytes(byte[] b) throws IOException, ClassNotFoundException {
ByteArrayInputStream stream = new ByteArrayInputStream(b);
return readExternalFormFromStream(stream);
}
protected boolean skipSerializedCanonicalTests() {
return Boolean.getBoolean("org.apache.commons.collections:with-clover");
}
// private implementation
//-----------------------------------------------------------------------
private Object readExternalFormFromStream(InputStream stream) throws IOException, ClassNotFoundException {
ObjectInputStream oStream = new ObjectInputStream(stream);
return oStream.readObject();
}
private void writeExternalFormToStream(Serializable o, OutputStream stream) throws IOException {
ObjectOutputStream oStream = new ObjectOutputStream(stream);
oStream.writeObject(o);
}
}