Poetic Walks(MIT software constraction) part1

Poetic Walks(MIT software constraction) part1

题目链接
该题目主要是训练java的泛型编程、AF（抽象函数) 、rep invariants(表示不变量）、mutable、immutable数据类型和preventing rep exposure（防御式编程）
ConcreteEdgesGraph和ConcreteVerticesGraph最大的区别在于EDGE类是immutable而Vertices类是mutable。
首先先编写关于Graph的测试函数GraphInstanceTest他其实是后面的编写的ConcreteEdgesGraphTest和ConcreteVerticesGraphTest的父类。
所以我们编写的GraphInstanceTest测试函数可以分为以下几种类型：

1. 测试add函数 按加入的点分类：点已存在，点不存在(重复输入)

@Testpublic void testAdd(){//Graph<String> Graph<String> test1=emptyInstance();String a="xu";String b="ya";test1.add(a);test1.add(b);assertEquals(true,test1.vertices().contains(a));assertEquals(true,test1.vertices().contains(b));assertEquals(false,test1.add(a));}

2.测试set函数

观察set函数的spec 可将测试划分为边已经存在，传入权值为0，移除边。传入权值大于0，更新边，返回原有边权值。传入权值小于0,return -1。边不存在,传入权值大于等于0加入顶点return 0，边不存在,传入权值小于0 return -1。

 @Testpublic void testset(){Graph<String> graph =emptyInstance();assertEquals(0,graph.set("a", "b", 5));assertEquals(0,graph.set("b", "c", 4));assertEquals(5,graph.set("a", "b", 6));assertEquals(6,graph.set("a", "b", 0));assertEquals(0,graph.set("a", "c", 0));assertEquals(-1,graph.set("a", "b", -3));	}

3.测试remove

 @Testpublic void testRemove() {Graph<String> test3=emptyInstance();test3.add("x");//test3.add();assertEquals(true,test3.vertices().contains("x"));ve("x");assertEquals(false,test3.vertices().contains("x"));}

4.测试vertices

//两种情况：空图，不是空图@Testpublic void testVertices() {testAdd();Graph<String> graph =emptyInstance();String a="a";String b="b";String c="c";graph.add(a);graph.add(b);graph.add(c);assertEquals(true,graph.vertices().contains(a));assertEquals(true,graph.vertices().contains(b));assertEquals(true,graph.vertices().contains(c));}

5.测试soureces

//两种情况：边已经存在，边不存在@Testpublic void testSources() {testAdd();testset();Graph<String> graph =emptyInstance();String a="a";String b="b";String c="c";graph.add(a);graph.add(b);graph.add(c);graph.set(a, b, 5);graph.set(b, c, 4);graph.set(a, c, 3);Map<String,Integer> map=new HashMap<String,Integer>();map.put(a,3);map.put(b,4);assertEquals(map,graph.sources(c)); 	}

6.测试targets

//两种情况：边已经存在，边不存在@Testpublic void testTargets() {testAdd();testset();Graph<String> graph =emptyInstance();String a="a";String b="b";String c="c";graph.add(a);graph.add(b);graph.add(c);graph.set(a, b, 5);graph.set(b, c, 4);graph.set(a, c, 3);Map<String,Integer> map=new HashMap<String,Integer>();map.put(c,3);map.put(b,5);assertEquals(map,graph.targets(a)); 	}