`1` ```exercism fetch csharp pov ```

#### PovTest.cs

 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154``` ```﻿using Xunit; using System.Linq; public class PovTest { private const string x = "x"; private static Graph leaf(T v) => Pov.CreateGraph(v, new Graph[0]); private static readonly Graph singleton = Pov.CreateGraph(x, new Graph[0]); private static readonly Graph flat = Pov.CreateGraph("root", new[] { "a", "b", x, "c" }.Select(leaf)); private static readonly Graph nested = Pov.CreateGraph("level-0", new[] { Pov.CreateGraph("level-1", new[] { Pov.CreateGraph("level-2", new[] { Pov.CreateGraph("level-3", new[] { Pov.CreateGraph(x, new Graph[0]) }) }) }) }); private static readonly Graph kids = Pov.CreateGraph("root", new[] { Pov.CreateGraph(x, new[] { Pov.CreateGraph("kid-0", new Graph[0]), Pov.CreateGraph("kid-1", new Graph[0]) }) }); private static readonly Graph cousins = Pov.CreateGraph("grandparent", new[] { Pov.CreateGraph("parent", new [] { Pov.CreateGraph(x, new [] { leaf("kid-a"), leaf("kid-b") }), leaf("sibling-0"), leaf("sibling-1") }), Pov.CreateGraph("uncle", new [] { leaf("cousin-0"), leaf("cousin-1") }) }); private static readonly Graph singleton_ = singleton; private static readonly Graph flat_ = Pov.CreateGraph(x, new[] { Pov.CreateGraph("root", new [] { "a", "b", "c" }.Select(leaf)) }); private static readonly Graph nested_ = Pov.CreateGraph(x, new[] { Pov.CreateGraph("level-3", new [] { Pov.CreateGraph("level-2", new [] { Pov.CreateGraph("level-1", new [] { Pov.CreateGraph("level-0", new Graph[0]) }) }) }) }); private static readonly Graph kids_ = Pov.CreateGraph(x, new[] { Pov.CreateGraph("kid-0", new Graph[0]), Pov.CreateGraph("kid-1", new Graph[0]), Pov.CreateGraph("root", new Graph[0]) }); private static readonly Graph cousins_ = Pov.CreateGraph(x, new[] { leaf("kid-a"), leaf("kid-b"), Pov.CreateGraph("parent", new [] { Pov.CreateGraph("sibling-0", new Graph[0]), Pov.CreateGraph("sibling-1", new Graph[0]), Pov.CreateGraph("grandparent", new [] { Pov.CreateGraph("uncle", new [] { Pov.CreateGraph("cousin-0", new Graph[0]), Pov.CreateGraph("cousin-1", new Graph[0]) }) }) }) }); [Fact] public void Reparent_singleton() { Assert.Equal(singleton_, Pov.FromPOV(x, singleton)); } [Fact(Skip = "Remove to run test")] public void Reparent_flat() { Assert.Equal(flat_, Pov.FromPOV(x, flat)); } [Fact(Skip = "Remove to run test")] public void Reparent_nested() { Assert.Equal(nested_, Pov.FromPOV(x, nested)); } [Fact(Skip = "Remove to run test")] public void Reparent_kids() { Assert.Equal(kids_, Pov.FromPOV(x, kids)); } [Fact(Skip = "Remove to run test")] public void Reparent_cousins() { Assert.Equal(cousins_, Pov.FromPOV(x, cousins)); } [Fact(Skip = "Remove to run test")] public void Reparent_from_POV_of_non_existent_node() { Assert.Null(Pov.FromPOV(x, leaf("foo"))); } [Fact(Skip = "Remove to run test")] public void Should_not_be_able_to_find_a_missing_node() { var nodes = new[] { singleton, flat, kids, nested, cousins }.Select(graph => Pov.FromPOV("NOT THERE", graph)); Assert.All(nodes, node => { Assert.Null(node); }); } [Fact(Skip = "Remove to run test")] public void Cannot_trace_between_unconnected_nodes() { Assert.Null(Pov.TracePathBetween(x, "NOT THERE", cousins)); } [Fact(Skip = "Remove to run test")] public void Can_trace_a_path_from_x_to_cousin() { Assert.Equal(new[] { "x", "parent", "grandparent", "uncle", "cousin-1" }, Pov.TracePathBetween(x, "cousin-1", cousins)); } [Fact(Skip = "Remove to run test")] public void Can_trace_from_a_leaf_to_a_leaf() { Assert.Equal(new[] { "kid-a", "x", "parent", "grandparent", "uncle", "cousin-0" }, Pov.TracePathBetween("kid-a", "cousin-0", cousins)); } } ```