public void DijkstraTest3_Success()
{
var graph = new DirectedWeightedGraph <char>(5);
var a = graph.AddVertex('A');
var b = graph.AddVertex('B');
var c = graph.AddVertex('C');
graph.AddEdge(a, b, 1);
graph.AddEdge(b, a, 1);
graph.AddEdge(a, c, 3);
graph.AddEdge(c, a, 3);
var shortestPathList = DijkstraAlgorithm.GenerateShortestPath(graph, a);
shortestPathList.Length.Should().Be(3);
shortestPathList[0].Vertex.Should().Be(a);
shortestPathList[0].Distance.Should().Be(0);
shortestPathList[0].PreviousVertex.Should().Be(a);
shortestPathList[0].ToString().Should()
.Be($"Vertex: {a} - Distance: {0} - Previous: {a}");
shortestPathList[1].Vertex.Should().Be(b);
shortestPathList[1].Distance.Should().Be(1);
shortestPathList[1].PreviousVertex.Should().Be(a);
shortestPathList[1].ToString().Should()
.Be($"Vertex: {b} - Distance: {1} - Previous: {a}");
shortestPathList[2].Vertex.Should().Be(c);
shortestPathList[2].Distance.Should().Be(3);
shortestPathList[2].PreviousVertex.Should().Be(a);
shortestPathList[2].ToString().Should()
.Be($"Vertex: {c} - Distance: {3} - Previous: {a}");
}
public void DijkstraMethodTest_ShouldThrow_VertexDoesntBelongToGraph()
{
var graph = new DirectedWeightedGraph <char>(5);
var startVertex = graph.AddVertex('A');
Func <DistanceModel <char>[]> action = () => DijkstraAlgorithm.GenerateShortestPath(
new DirectedWeightedGraph <char>(5), startVertex);
action.Should().Throw <ArgumentNullException>()
.WithMessage($"Value cannot be null. (Parameter '{nameof(graph)}')");
}
public void DijkstraTest4_Success()
{
var graph = new DirectedWeightedGraph <char>(5);
var a = graph.AddVertex('A');
var b = graph.AddVertex('B');
var c = graph.AddVertex('C');
var d = graph.AddVertex('D');
graph.AddEdge(a, b, 1);
graph.AddEdge(b, a, 1);
graph.AddEdge(a, c, 3);
graph.AddEdge(c, a, 3);
graph.AddEdge(c, d, 5);
graph.AddEdge(d, c, 5);
var shortestPathList = DijkstraAlgorithm.GenerateShortestPath(graph, a);
shortestPathList.Length.Should().Be(4);
shortestPathList[0].Vertex.Should().Be(a);
shortestPathList[0].Distance.Should().Be(0);
shortestPathList[0].PreviousVertex.Should().Be(a);
shortestPathList[0].ToString().Should()
.Be($"Vertex: {a} - Distance: {0} - Previous: {a}");
shortestPathList[1].Vertex.Should().Be(b);
shortestPathList[1].Distance.Should().Be(1);
shortestPathList[1].PreviousVertex.Should().Be(a);
shortestPathList[1].ToString().Should()
.Be($"Vertex: {b} - Distance: {1} - Previous: {a}");
shortestPathList[2].Vertex.Should().Be(c);
shortestPathList[2].Distance.Should().Be(3);
shortestPathList[2].PreviousVertex.Should().Be(a);
shortestPathList[2].ToString().Should()
.Be($"Vertex: {c} - Distance: {3} - Previous: {a}");
// Vertex D won't be visited in this dijkstra implementation which is valid only for cyclic graphs,
// since it is necessary to backtrack all unvisited vertices and place them
// to the priority queue, which is not implemented yet in this repository.
// If algo goes to the next vertex with minimal distance and this vertex is leaf -- algorithm stops.
shortestPathList[3].Vertex.Should().Be(d);
shortestPathList[3].Distance.Should().Be(double.MaxValue);
shortestPathList[3].PreviousVertex.Should().BeNull();
shortestPathList[3].ToString().Should()
.Be($"Vertex: {d} - Distance: {double.MaxValue} - Previous: {null}");
}
public void DijkstraTest1_Success()
{
// here test case is from https://www.youtube.com/watch?v=pVfj6mxhdMw
var graph = new DirectedWeightedGraph <char>(5);
var a = graph.AddVertex('A');
var b = graph.AddVertex('B');
var c = graph.AddVertex('C');
var d = graph.AddVertex('D');
var e = graph.AddVertex('E');
graph.AddEdge(a, b, 6);
graph.AddEdge(b, a, 6);
graph.AddEdge(a, d, 1);
graph.AddEdge(d, a, 1);
graph.AddEdge(d, e, 1);
graph.AddEdge(e, d, 1);
graph.AddEdge(d, b, 2);
graph.AddEdge(b, d, 2);
graph.AddEdge(e, b, 2);
graph.AddEdge(b, e, 2);
graph.AddEdge(e, c, 5);
graph.AddEdge(c, e, 5);
graph.AddEdge(c, b, 5);
graph.AddEdge(b, c, 5);
var shortestPathList = DijkstraAlgorithm.GenerateShortestPath(graph, a);
shortestPathList.Length.Should().Be(5);
shortestPathList[0].Vertex.Should().Be(a);
shortestPathList[0].Distance.Should().Be(0);
shortestPathList[0].PreviousVertex.Should().Be(a);
shortestPathList[0].ToString().Should()
.Be($"Vertex: {a} - Distance: {0} - Previous: {a}");
shortestPathList[1].Vertex.Should().Be(b);
shortestPathList[1].Distance.Should().Be(3);
shortestPathList[1].PreviousVertex.Should().Be(d);
shortestPathList[1].ToString().Should()
.Be($"Vertex: {b} - Distance: {3} - Previous: {d}");
shortestPathList[2].Vertex.Should().Be(c);
shortestPathList[2].Distance.Should().Be(7);
shortestPathList[2].PreviousVertex.Should().Be(e);
shortestPathList[2].ToString().Should()
.Be($"Vertex: {c} - Distance: {7} - Previous: {e}");
shortestPathList[3].Vertex.Should().Be(d);
shortestPathList[3].Distance.Should().Be(1);
shortestPathList[3].PreviousVertex.Should().Be(a);
shortestPathList[3].ToString().Should()
.Be($"Vertex: {d} - Distance: {1} - Previous: {a}");
shortestPathList[4].Vertex.Should().Be(e);
shortestPathList[4].Distance.Should().Be(2);
shortestPathList[4].PreviousVertex.Should().Be(d);
shortestPathList[4].ToString().Should()
.Be($"Vertex: {e} - Distance: {2} - Previous: {d}");
}
