src/test/org/apache/commons/math/MathExceptionTest.java

/*
 * Copyright 2003-2004 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.math;

import junit.framework.TestCase;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * @version $Revision$ $Date$
 */
public class MathExceptionTest extends TestCase {
    /**
     * 
     */
    public void testConstructor(){
        MathException ex = new MathException();
        assertNull(ex.getCause());
        assertNull(ex.getMessage());
    }
    
    /**
     * 
     */
    public void testConstructorMessage(){
        String msg = "message";
        MathException ex = new MathException(msg);
        assertNull(ex.getCause());
        assertEquals(msg, ex.getMessage());
    }
    
    /**
     * 
     */
    public void testConstructorMessageCause(){
        String outMsg = "outer message";
        String inMsg = "inner message";
        Exception cause = new Exception(inMsg);
        MathException ex = new MathException(outMsg, cause);
        assertEquals(outMsg, ex.getMessage());
        assertEquals(cause, ex.getCause());
    }
    
    /**
     * 
     */
    public void testConstructorCause(){
        String inMsg = "inner message";
        Exception cause = new Exception(inMsg);
        MathException ex = new MathException(cause);
        assertEquals(cause, ex.getCause());
    }
    
    /**
     * Tests the printStackTrace() operation.
     */
    public void testPrintStackTrace() {
        String outMsg = "outer message";
        String inMsg = "inner message";
        MathException cause = new MathConfigurationException(inMsg);
        MathException ex = new MathException(outMsg, cause);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PrintStream ps = new PrintStream(baos);
        ex.printStackTrace(ps);
        String stack = baos.toString();
        String outerMsg = "org.apache.commons.math.MathException: outer message";
        String innerMsg = "Caused by: " + 
        "org.apache.commons.math.MathConfigurationException: inner message";
        assertTrue(stack.startsWith(outerMsg));
        assertTrue(stack.indexOf(innerMsg) > 0);
        
        PrintWriter pw = new PrintWriter(ps, true);
        ex.printStackTrace(pw);
        stack = baos.toString();
        assertTrue(stack.startsWith(outerMsg));
        assertTrue(stack.indexOf(innerMsg) > 0);
    }
    
    /**
     * Test serialization
     */
    public void testSerialization() {
        String outMsg = "outer message";
        String inMsg = "inner message";
        MathException cause = new MathConfigurationException(inMsg);
        MathException ex = new MathException(outMsg, cause);
        MathException image = (MathException) TestUtils.serializeAndRecover(ex);
        
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PrintStream ps = new PrintStream(baos);
        PrintWriter pw = new PrintWriter(ps, true);
        ex.printStackTrace(ps);
        String stack = baos.toString();
        
        ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
        PrintStream ps2 = new PrintStream(baos2);
        PrintWriter pw2 = new PrintWriter(ps2, true);
        image.printStackTrace(ps2);
        String stack2 = baos2.toString();
        
        // See if JDK supports nested exceptions.  If not, stack trace of
        // inner exception will not be serialized
        boolean jdkSupportsNesting = false;
        try {
            Throwable.class.getDeclaredMethod("getCause", new Class[0]);
            jdkSupportsNesting = true;
        } catch (NoSuchMethodException e) {
            jdkSupportsNesting = false;
        }
        
        if (jdkSupportsNesting) {
            assertEquals(stack, stack2);
        } else {
            assertTrue(stack2.indexOf(inMsg) != -1);
            assertTrue(stack2.indexOf("MathConfigurationException") != -1);
        }
    }
}