TDD方法与简单解决方案
TDD方法与简单解决方案
提问于 2013-03-20 15:22:36
您可以为下面的枚举类编写多少个测试。给定以下命令，我将查找以下输出：
java fileName HORIZON_BOX, HORIZON_BOX_WITH_CC, HORIZON_BOX_WITH_CC
1 HORIZON_BOX: 20.00
2 HORIZON_BOX_WITH_CC @ 30.00 : 60.00
GRAND TOTAL : 80.00解决这个问题最好的解决方法是什么？
public enum Product {
HORIZON_BOX(30.00),
HORIZON_BOX_WITH_CC(50.00),
HORIZON_BOX_WITH_CC_2_TB(100.00),
HORIZON_MULTIROOM(75.00),
HUB(20.00);
private double price;
private Product(double price) {
this.price = price;
}
public double getPrice() {
return price;
}
}我所作的测试如下：
public class ProductTest {
/**
* Test that fails as we cannot access the private constructor of the Enum
* Written before any code is written to test
*/
@Test
public void testProductNothingImplemented() {
// Product("Nothing has been implemented yet");
}
/**
* Test expectedvalue of 20
*/
@Test
public void testProductHORIZONBoxHUB() {
assertEquals(20, Product.HUB.getPrice(), 0);
}
/**
* Test expectedvalue of 50 for HORIZON_BOX_WITH_HD
*/
@Test
public void testProductHORIZON_BOX_WITH_HD() {
assertEquals(50, Product.HORIZON_BOX_WITH_CC.getPrice(), 0);
}
/**
* Test expectedvalue of 100 for HORIZON_BOX_WITH_HD_2_TB
*/
@Test
public void testProductHORIZON_BOX_WITH_HD_2_TB() {
assertEquals(100, Product.HORIZON_BOX_WITH_CC_2_TB.getPrice(), 0);
}
/**
* Test expectedvalue of 75 for HORIZON_MULTIROOM
*/
@Test
public void testProductHORIZON_MULTIROOM() {
assertEquals(75, Product.HORIZON_MULTIROOM.getPrice(), 0);
}
/**
* Test expectedvalue of 30 for HORIZON_BOX
*/
@Test
public void testProductHORIZON_BOX() {
assertEquals(30, Product.HORIZON_BOX.getPrice(), 0);
}
/**
* test method to compute total with zero products
*/
@Test
public void testComputeEmptyMap() {
Map<String, Integer> testMap = new HashMap<String, Integer>();
//setup map
Horizon Horizon = new Horizon();
assertEquals(new Double(0), Horizon.computeAndPrintTotal(testMap));
}
/**
* test method to compute total with two elements but second element is ) products
*/
@Test
public void testComputeAndPrintTotalWithOneProductHavingZeroFrequency() {
Map<String, Integer> testMap = new HashMap<String, Integer>();
//setup map
testMap.put("HUB", 1);
testMap.put("HORIZON_BOX", 0);
Horizon Horizon = new Horizon();
assertEquals(new Double(20), Horizon.computeAndPrintTotal(testMap));
}
/**
* test method to compute total with two products
*/
@Test
public void testComputeAndPrintTotalPass() {
Map<String, Integer> testMap = new HashMap<String, Integer>();
testMap.put("HUB", 1);
testMap.put("HORIZON_BOX", 2);
Horizon Horizon = new Horizon();
assertEquals(new Double(80), Horizon.computeAndPrintTotal(testMap));
}
}
#######################################################################################我拥有以下内容:执行的主类是
public class Horizon {
private Map<String, Integer> argFrequencyCount = new HashMap<String, Integer>();
double total = 0;
@SuppressWarnings("rawtypes")
public static void main(String[] args) {
Horizon horizon = new Horizon();
for (String productName : args) {
Integer frequency = horizon.argFrequencyCount.get(productName);
horizon.argFrequencyCount.put(productName, (frequency == null) ? 1
: frequency + 1);
}
horizon.argFrequencyCount = horizon.sortProductMapByFrequency(horizon.argFrequencyCount);
for (Iterator iterator = horizon.argFrequencyCount.entrySet().iterator(); iterator
.hasNext();) {
@SuppressWarnings("unchecked")
Map.Entry<String, Integer> productCount = (Map.Entry<String, Integer>) iterator
.next();
horizon.outputPrintHelper(productCount.getKey(),
productCount.getValue());
}
horizon.computeAndPrintTotal(horizon.argFrequencyCount);
}
/**
* method to print total
*
* @param argFrequencyCount
*/
public Double computeAndPrintTotal(Map<String, Integer> argFrequencyCount) {
for (Iterator<Map.Entry<String, Integer>> iterator = argFrequencyCount.entrySet().iterator(); iterator
.hasNext();) {
Map.Entry<String, Integer> productCount = (Map.Entry<String, Integer>) iterator
.next();
total = total + productCount.getValue()
* Product.valueOf(productCount.getKey()).getPrice();
}
System.out.println("GRAND TOTAL : £" + total);
return total;
}
/**
* Method to print the items and corresponding item total
*
* @param prod
* @param numberOfItems
*/
private void outputPrintHelper(String prod, int numberOfItems) {
Product product = Product.valueOf(prod);
switch (product) {
case HUB:
if (numberOfItems == 1) {
System.out.println(numberOfItems + " HUB : £"
+ Product.HUB.getPrice());
} else {
System.out.println(numberOfItems + " HUB @ £" + Product.HUB
+ " : £" + numberOfItems * Product.HUB.getPrice());
}
break;
case HORIZON_BOX:
if (numberOfItems == 1) {
System.out.println(numberOfItems + " HORIZON_BOX : £"
+ Product.HORIZON_BOX.getPrice());
} else {
System.out.println(numberOfItems + " HORIZON_BOX @ £"
+ Product.HORIZON_BOX.getPrice() + " : £" + numberOfItems
* Product.HORIZON_BOX.getPrice());
}
break;
case HORIZON_BOX_WITH_CC:
if (numberOfItems == 1) {
System.out.println(numberOfItems + " HORIZON_BOX_WITH_CC : £"
+ Product.HORIZON_BOX_WITH_CC.getPrice());
} else {
System.out.println(numberOfItems + " HORIZON_BOX_WITH_CC @ £"
+ Product.HORIZON_BOX_WITH_CC.getPrice() + " : £"
+ numberOfItems * Product.HORIZON_BOX_WITH_CC.getPrice());
}
break;
case HORIZON_BOX_WITH_CC_2_TB:
if (numberOfItems == 1) {
System.out.println(numberOfItems + " HORIZON_BOX_WITH_CC_2_TB : £"
+ Product.HORIZON_BOX_WITH_CC_2_TB.getPrice());
} else {
System.out.println(numberOfItems
+ " HORIZON_BOX_WITH_CC_2_TB @ £"
+ Product.HORIZON_BOX_WITH_CC_2_TB.getPrice() + " : £"
+ numberOfItems
* Product.HORIZON_BOX_WITH_CC_2_TB.getPrice());
}
break;
case HORIZON_MULTIROOM:
if (numberOfItems == 1) {
System.out.println(numberOfItems + " HORIZON_MULTIROOM : £"
+ Product.HORIZON_MULTIROOM.getPrice());
} else {
System.out.println(numberOfItems + " HORIZON_MULTIROOM @ £"
+ Product.HORIZON_MULTIROOM.getPrice() + " : £"
+ numberOfItems * Product.HORIZON_MULTIROOM.getPrice());
}
}
}
/**
* Sort the HashMap by number of items in descending order
*
*/
private Map<String, Integer> sortProductMapByFrequency(
Map<String, Integer> passedMap) {
List<String> mapKeys = new ArrayList<String>(passedMap.keySet());
List<Integer> mapValues = new ArrayList<Integer>(passedMap.values());
Collections.sort(mapValues);
Collections.sort(mapKeys);
LinkedHashMap<String, Integer> sortedMap = new LinkedHashMap<String, Integer>();
Iterator<Integer> valueIt = mapValues.iterator();
while (valueIt.hasNext()) {
Object val = valueIt.next();
Iterator<String> keyIt = mapKeys.iterator();
while (keyIt.hasNext()) {
Object key = keyIt.next();
String comp1 = passedMap.get(key).toString();
String comp2 = val.toString();
if (comp1.equals(comp2)) {
passedMap.remove(key);
mapKeys.remove(key);
sortedMap.put((String) key, (Integer) val);
break;
}
}
}
return sortedMap;
}
}回答 1
Code Review用户
发布于 2013-03-22 07:02:12
@David很好地回答了关于测试的问题，没有什么重要的补充。在第二个问题审查设计时，设计也有一些重要的问题，但我不想让以下几点落空：
- 对于泛型来说，您似乎是新手：@SuppressWarnings(“rawtype”)如果您使用了
Iterator<Map.Entry<String, Integer>>而不是原始的Iterator，那么您不仅可以避免这个警告，还可以避免未检查的强制转换(以及附带的警告)。 - 当您在集合中迭代时，您应该更倾向于每种语法，除非您要在循环中添加或删除元素。比较: for (Iterator iterator = horizon.argFrequencyCount.entrySet() .iterator()；iterator.hasNext();) {@SuppressWarnings(“未检查”) Map.Entry productCount = (Map.Entry) iterator.next()；以下为: for (Map.Entry productCount : horizon.argFrequencyCount.entrySet()) {
- 应该将各种
Map<String, Integer>更改为Map<Product, Integer>；因为这些映射包含“每个产品的数量”。 - 您在这里丢失了类型信息: Iterator valueIt = mapValues.iterator()；Object val = valueIt.next()；Iterator valueIt = mapValues.iterator()；int val = valueIt.next()；//您应该使用Integer = valueIt.next()；//如果val可能为null，这里不需要--这里的每个循环也都有帮助。
- 由于您丢失了上面的类型信息；您正在比较对象的字符串表示形式: string comp1 = passedMap.get(key).toString()；String comp2 = val.toString()；if (comp1.Eques(Comp2)){相反，您可以编写: if (passedMap.get(key).equals(val)) {
- 这个片段的另一点是
passedMap，key和val根本不是描述性的。现在比较一下: if (passedMap.get(key).equals(val)) {与: if .equals{哪个读得更好？名字很重要。 - 这里是
sortProductMapByFrequency的签名:私有Map sortProductMapByFrequency( Map passedMap) {返回值的契约应该从签名中明显看出。如果要对集合进行排序，则返回值应该有一定的顺序。因此，至少您应该显式地返回一个LinkedHashMap。如果要根据键对地图条目进行排序，则应该返回一个SortedMap。因为您根据值(而不仅仅是键)对条目进行排序，所以不能。如果您要对一个List<Map.Entry<X,Y>>的条目进行排序，那么我希望得到一个Map<X,Y>。你不能用SortedMap，straightforwardly，但是您可以使用排序的多个时间点，例如，如果您有ApacheCommons或Guava。这里有一个可维护性的权衡。 - 另外，当您遍历一个映射并同时使用键和值时，您应该像在其他地方那样使用entrySet来迭代。这样，嵌套循环就可以是一个循环，效率更高、可读性更强。或者您可以这样做:私有List> sortProductMapByFrequency( Map productFrequencies) { List>条目=新ArrayList>(productFrequencies.entrySet())；Collections.sort(条目，compareProductFrequencies()；返回条目；} Comparator> compareProductFrequencies() {返回新的Comparator>() {@覆盖公共int比较( Entry lhs，Entry rhs) {返回lhs.getValue().compareTo(rhs.getValue())；}；}
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原文链接：
https://codereview.stackexchange.com/questions/24161
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