/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.analysis.solvers;

import junit.framework.TestCase;

import org.apache.commons.math.MathException;
import org.apache.commons.math.analysis.SinFunction;
import org.apache.commons.math.analysis.UnivariateRealFunction;

/**
 * @version $Revision$ $Date$
 */
public class UnivariateRealSolverUtilsTest extends TestCase {

	protected UnivariateRealFunction sin = new SinFunction();

	public void testSolveNull() throws MathException {
		try {
			UnivariateRealSolverUtils.solve(null, 0.0, 4.0);
			fail();
		} catch (IllegalArgumentException ex) {
			// success
		}
	}

	public void testSolveBadParameters() throws MathException {
		try { // bad endpoints
			UnivariateRealSolverUtils.solve(sin, 0.0, 4.0, 4.0);
		} catch (IllegalArgumentException ex) {
			// expected
		}
		try { // bad accuracy
			UnivariateRealSolverUtils.solve(sin, 0.0, 4.0, 0.0);
		} catch (IllegalArgumentException ex) {
			// expected
		}
	}

	public void testSolveSin() throws MathException {
		double x = UnivariateRealSolverUtils.solve(sin, 1.0, 4.0);
		assertEquals(Math.PI, x, 1.0e-4);
	}

	public void testSolveAccuracyNull() throws MathException {
		try {
			double accuracy = 1.0e-6;
			UnivariateRealSolverUtils.solve(null, 0.0, 4.0, accuracy);
			fail();
		} catch (IllegalArgumentException ex) {
			// success
		}
	}

	public void testSolveAccuracySin() throws MathException {
		double accuracy = 1.0e-6;
		double x = UnivariateRealSolverUtils.solve(sin, 1.0, 4.0, accuracy);
		assertEquals(Math.PI, x, accuracy);
	}

	public void testSolveNoRoot() throws MathException {
		try {
			UnivariateRealSolverUtils.solve(sin, 1.0, 1.5);
			fail("Expecting IllegalArgumentException ");
		} catch (IllegalArgumentException ex) {
			// expected
		}
	}

	public void testBracketSin() throws MathException {
		double[] result = UnivariateRealSolverUtils.bracket(sin, 0.0, -2.0, 2.0);
		assertTrue(sin.value(result[0]) < 0);
		assertTrue(sin.value(result[1]) > 0);
	}

	public void testBadParameters() throws MathException {
		try { // null function
			UnivariateRealSolverUtils.bracket(null, 1.5, 0, 2.0);
			fail("Expecting IllegalArgumentException");
		} catch (IllegalArgumentException ex) {
			// expected
		}
		try { // initial not between endpoints
			UnivariateRealSolverUtils.bracket(sin, 2.5, 0, 2.0);
			fail("Expecting IllegalArgumentException");
		} catch (IllegalArgumentException ex) {
			// expected
		}
		try { // endpoints not valid
			UnivariateRealSolverUtils.bracket(sin, 1.5, 2.0, 1.0);
			fail("Expecting IllegalArgumentException");
		} catch (IllegalArgumentException ex) {
			// expected
		}
		try { // bad maximum iterations
			UnivariateRealSolverUtils.bracket(sin, 1.5, 0, 2.0, 0);
			fail("Expecting IllegalArgumentException");
		} catch (IllegalArgumentException ex) {
			// expected
		}
	}

}
