1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/task4/solution12/test/org/apidesign/apifest08/test/Task3Test.java Sat Oct 11 23:38:46 2008 +0200
1.3 @@ -0,0 +1,145 @@
1.4 +package org.apidesign.apifest08.test;
1.5 +
1.6 +import java.util.Currency;
1.7 +
1.8 +import junit.framework.TestCase;
1.9 +import org.apidesign.apifest08.currency.Convertor;
1.10 +import org.apidesign.apifest08.currency.exceptions.UnknownConvertorException;
1.11 +
1.12 +/** The exchange rates are not always the same. They are changing. Day by day,
1.13 + * hour by hour, minute by minute. For every bank it is important to always
1.14 + * have the actual exchange rate available in the system. That is why let's
1.15 + * create a pluggable convertor that will always have up to date value of its
1.16 + * exchange rate.
1.17 + * <p>
1.18 + * The quest for today is to allow 3rd party developer to write a convertor
1.19 + * that adjusts its exchange rate everytime it is queried. This convertor is
1.20 + * written by independent vendor, the vendor knows only your Convertor API,
1.21 + * he does not know how the whole system looks and how the convertor is supposed
1.22 + * to be used.
1.23 + */
1.24 +public class Task3Test extends TestCase {
1.25 +
1.26 + private static double actualRate;
1.27 + private static boolean increasing;
1.28 +
1.29 + private static final double EXCHANGE_RATE_MAX = 16.0;
1.30 + private static final double EXCHANGE_RATE_MIN = 15.0;
1.31 +
1.32 + public Task3Test(String testName) {
1.33 + super(testName);
1.34 + }
1.35 +
1.36 + @Override
1.37 + protected void setUp() throws Exception {
1.38 + }
1.39 +
1.40 + @Override
1.41 + protected void tearDown() throws Exception {
1.42 + }
1.43 +
1.44 + // Backward compatibly enhance your existing API to support following
1.45 + // usecases:
1.46 + //
1.47 +
1.48 +
1.49 + /** Without knowing anything about the surrounding system, write an
1.50 + * implementation of convertor that will return different rates everytime
1.51 + * it is queried. Convert USD to CZK and vice versa. Start with the rate of
1.52 + * 1USD = 16CZK and adjust it in favor of CZK by 0.01 CZK with every query.
1.53 + * As soon as you reach 1USD = 15CZK adjust it by 0.01 CZK in favor of USD
1.54 + * until you reach 1USD = 16CZK
1.55 + *
1.56 + * @return new instance of "online" USD and CZK convertor starting with rate 1USD = 16CZK
1.57 + */
1.58 + public static Convertor createOnlineCZKUSDConvertor() {
1.59 + actualRate = 16.01;
1.60 + increasing = false;
1.61 +
1.62 + // sets actual exchange rates
1.63 + setRates();
1.64 +
1.65 + // create new instance
1.66 + Convertor convertor = null;
1.67 + try {
1.68 + convertor = Convertor.getConvertorInstance(Currency.getInstance("USD"), Currency.getInstance("CZK"));
1.69 + } catch (UnknownConvertorException e) {
1.70 + e.printStackTrace();
1.71 + }
1.72 +
1.73 + return convertor;
1.74 + }
1.75 +
1.76 + public void testFewQueriesForOnlineConvertor() throws Exception {
1.77 + Convertor c = createOnlineCZKUSDConvertor();
1.78 + doFewQueriesForOnlineConvertor(c);
1.79 + }
1.80 +
1.81 + static void doFewQueriesForOnlineConvertor(Convertor c) throws Exception {
1.82 + // convert $5 to CZK using c:
1.83 + double result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
1.84 + double expectedResult = actualRate * 5;
1.85 + assertEquals("Result is not " + expectedResult + " CZK", expectedResult, result);
1.86 +
1.87 + // change exchange rates
1.88 + setRates();
1.89 +
1.90 + // convert $8 to CZK using c:
1.91 + result = c.convert(8d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
1.92 + expectedResult = actualRate * 8;
1.93 + assertEquals("Result is not " + expectedResult + " CZK", expectedResult, result);
1.94 +
1.95 + // change exchange rates
1.96 + setRates();
1.97 +
1.98 + // convert $1 to CZK using c:
1.99 + result = c.convert(1d, Currency.getInstance("USD"), Currency.getInstance("CZK"));
1.100 + expectedResult = actualRate * 1;
1.101 + assertEquals("Result is not " + expectedResult + " CZK", expectedResult, result);
1.102 +
1.103 + // change exchange rates
1.104 + setRates();
1.105 +
1.106 + // convert 15.97CZK to USD using c:
1.107 + result = c.convert(15.97d, Currency.getInstance("CZK"), Currency.getInstance("USD"));
1.108 + expectedResult = 15.97 / actualRate ;
1.109 + assertEquals("Result is not " + expectedResult + " USD", expectedResult, result);
1.110 + }
1.111 +
1.112 + /** Join the convertors and show they behave sane.
1.113 + */
1.114 + public void testOnlineConvertorComposition() throws Exception {
1.115 + Convertor c = Task2Test.merge(
1.116 + createOnlineCZKUSDConvertor(),
1.117 + Task1Test.createSKKtoCZK()
1.118 + );
1.119 +
1.120 + // convert 16CZK to SKK using c:
1.121 + double result = c.convert(16d, Currency.getInstance("CZK"), Currency.getInstance("SKK"));
1.122 + assertEquals("Result is not 20 SKK", 20d, result);
1.123 +
1.124 + // convert 500SKK to CZK using c:
1.125 + result = c.convert(500d, Currency.getInstance("SKK"), Currency.getInstance("CZK"));
1.126 + assertEquals("Result is not 400 CZK", 400d, result);
1.127 +
1.128 + doFewQueriesForOnlineConvertor(c);
1.129 + }
1.130 +
1.131 + private static void setRates() {
1.132 + // logic for change of actual exchange rate
1.133 + if(increasing) {
1.134 + actualRate += 0.01;
1.135 + if(actualRate == EXCHANGE_RATE_MAX){
1.136 + increasing = false;
1.137 + }
1.138 + } else {
1.139 + actualRate -= 0.01;
1.140 + if(actualRate == EXCHANGE_RATE_MIN){
1.141 + increasing = true;
1.142 + }
1.143 + }
1.144 +
1.145 + // set exchange rates
1.146 + Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("CZK"), actualRate, 1d);
1.147 + }
1.148 +}