/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * 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.wamblee.test;

import java.util.Arrays;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import java.util.logging.Logger;

import junit.framework.TestCase;

/**
 * Useful assertions for use in test cases.
 * 
 * @author Erik Brakkee
 */
public final class AssertionUtils {
    private static final Logger LOG = Logger.getLogger(AssertionUtils.class
        .getName());

    /**
     * Disabled constructor.
     * 
     */
    private AssertionUtils() {
        // Empty
    }

    /**
     * Asserts that two object arrays are equal.
     * 
     * @param aExpected
     *            Expected object array.
     * @param aActual
     *            Actual object array.
     */
    public static <T> void assertEquals(T[] aExpected, T[] aActual) {
        assertEquals("", aExpected, aActual);
    }

    /**
     * Asserts that two object arrays are equal.
     * 
     * @param aMsg
     *            Message.
     * @param aExpected
     *            Expected array.
     * @param aActual
     *            Actual array.
     */
    public static <T> void assertEquals(String aMsg, T[] aExpected, T[] aActual) {
        TestCase.assertEquals(aMsg + " expected " + Arrays.asList(aExpected) +
            ", actual " + Arrays.asList(aActual) + ": Array lengths ",
            aExpected.length, aActual.length);

        for (int i = 0; i < aExpected.length; i++) {
            TestCase.assertEquals(aMsg + ": Element " + i, aExpected[i],
                aActual[i]);
        }
    }

/**
     * Asserts that two objects are equal, and in case the object is an Object[]
     * delegates to {@link #assertEquals(String, Object[], Object[])}.
     *
     * @param aMsg
     *            Message.
     * @param aExpected
     *            Expected result.
     * @param aActual
     *            Actual result.
     */
    public static <T> void assertEquals(String aMsg, T aExpected, T aActual) {
        if (aExpected instanceof Object[]) {
            AssertionUtils.assertEquals(aMsg, (Object[]) aExpected,
                (Object[]) aActual);

            return;
        }

        TestCase.assertEquals(aMsg, aExpected, aActual);
    }

    /**
     * Asserts that two maps are equal by comparing all keys and by checking
     * that the values for the same keys are the same.
     * 
     * @param aMsg
     *            Message.
     * @param aExpectedMap
     *            Expected result.
     * @param aActual
     *            Actual result.
     */
    public static <Key, Value> void assertEquals(String aMsg,
        Map<Key, Value> aExpectedMap, Map<Key, Value> aActual) {
        TestCase.assertEquals("Map sizes differ", aExpectedMap.size(), aActual
            .size());

        Set<Entry<Key, Value>> expectedEntries = aExpectedMap.entrySet();

        for (Entry<Key, Value> entry : expectedEntries) {
            Key key = entry.getKey();
            TestCase.assertTrue("Map does not containg entry for key:" + key,
                aActual.containsKey(key));
            AssertionUtils.assertEquals("Value of key " + key + " of map",
                entry.getValue(), aActual.get(key));
        }
    }

    /**
     * Asserts that an exception occurs.
     * 
     * @param aObject Erroneious code.
     *            Test cases should create a subclass of this which contains the
     *            code that should throw an exception.
     * @param aType
     *            Type of exception that is expected.
     */
    public static void assertException(ErroneousCode aObject, Class aType) {
        try {
            aObject.run();
            throw new RuntimeException("No exception occurred");
        } catch (Throwable t) {
            if (aType.isInstance(t)) {
                LOG.info("Expected exception occured " + t.getMessage());

                return; // ok
            }
            throw new RuntimeException(t);
        }
    }

    public static interface ErroneousCode {
        void run() throws Exception;
    }
}