+ distance vector (for sankey)

PSGraph.Common/Model/PSDistanceVectorRecord.cs

@@ -0,0 +1,11 @@
+using System;
+using PSGraph.Model;
+
+namespace PSGraph.Common.Model;
+
+public class PSDistanceVectorRecord
+{
+    public required PSVertex Vertex;
+    public double Level;
+
+}

PSGraph.Tests/GetGraphDistanceVectorTests.cs

@@ -0,0 +1,84 @@
+using Xunit;
+using System;
+using System.Management.Automation;
+using PSGraph.Model;
+using FluentAssertions;
+using System.Collections.Generic;
+using System.Linq;
+using PSGraph.Common.Model;
+
+namespace PSGraph.Tests
+{
+    public class GetGraphDistanceVectorCmdletTests : IDisposable
+    {
+        private PowerShell _powershell;
+
+        public GetGraphDistanceVectorCmdletTests()
+        {
+            _powershell = PowerShell.Create();
+            _powershell.AddCommand("Import-Module")
+                .AddParameter("Assembly", typeof(PSGraph.Cmdlets.GetGraphDistanceVector).Assembly);
+            _powershell.Invoke();
+            _powershell.Commands.Clear();
+        }
+
+        public void Dispose()
+        {
+            _powershell.Dispose();
+        }
+
+        [Fact]
+        public void GetGraphDistanceVector_ValidAcyclicGraph_ReturnsDistances()
+        {
+            // Arrange
+            _powershell.AddCommand("New-Graph");
+            var graphResults = _powershell.Invoke();
+            var graph = graphResults[0].BaseObject as PsBidirectionalGraph;
+
+            _powershell.Commands.Clear();
+
+            var vertexA = new PSVertex("A");
+            var vertexB = new PSVertex("B");
+            var vertexC = new PSVertex("C");
+
+            graph.AddVertexRange(new[] { vertexA, vertexB, vertexC });
+            graph.AddEdge(new PSEdge(vertexA, vertexB, new PSEdgeTag()));
+            graph.AddEdge(new PSEdge(vertexB, vertexC, new PSEdgeTag()));
+
+            _powershell.AddCommand("Get-GraphDistanceVector")
+                .AddParameter("Graph", graph);
+
+            // Act
+            var results = _powershell.Invoke();
+
+            // Assert
+            results.Should().NotBeNullOrEmpty();
+
+            var distances = results.Select(r => r.BaseObject as PSDistanceVectorRecord).ToList();
+            distances.Should().NotBeNull();
+            distances.Should().Contain(d => d.Vertex == vertexA && d.Level == 0);
+            distances.Should().Contain(d => d.Vertex == vertexB && d.Level == 1);
+            distances.Should().Contain(d => d.Vertex == vertexC && d.Level == 2);
+        }
+
+        [Fact]
+        public void GetGraphDistanceVector_EmptyGraph_ReturnsEmptyDistances()
+        {
+            // Arrange
+            _powershell.AddCommand("New-Graph");
+            var graphResults = _powershell.Invoke();
+            var graph = graphResults[0].BaseObject as PsBidirectionalGraph;
+
+            _powershell.Commands.Clear();
+
+            _powershell.AddCommand("Get-GraphDistanceVector")
+                .AddParameter("Graph", graph);
+
+            // Act
+            var results = _powershell.Invoke();
+
+            // Assert
+            results.Should().BeEmpty("because the graph is empty and has no vertices to calculate distances");
+        }
+    }
+}

PSGraphv2/cmdlets/graph/GetGraphDistanceVector.cs

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+using System;
+using System.Management.Automation;
+using QuikGraph.Algorithms;
+using PSGraph.Model;
+using System.Collections.Generic;
+using QuikGraph.Algorithms.TopologicalSort;
+using QuikGraph.Algorithms.Search;
+using QuikGraph.Algorithms.Observers;
+using System.Diagnostics.CodeAnalysis;
+using PSGraph.Common.Model;
+namespace PSGraph.Cmdlets
+{
+    [Cmdlet(VerbsCommon.Get, "GraphDistanceVector")]
+    public class GetGraphDistanceVector : PSCmdlet
+    {
+        [Parameter(Mandatory = true)]
+        [ValidateNotNullOrEmpty]
+        public PsBidirectionalGraph Graph;
+
+        protected override void EndProcessing()
+        {
+
+            var dfs = new DepthFirstSearchAlgorithm<PSVertex, PSEdge>(Graph);
+            var distanceRecorder = new VertexDistanceRecorderObserver<PSVertex, PSEdge>(v => 1);
+
+            var rootVertices = Graph.Vertices.Where(v => Graph.InDegree(v) == 0);
+
+            using (distanceRecorder.Attach(dfs))
+            {
+                foreach (var vertex in rootVertices)
+                {
+                    dfs.SetRootVertex(vertex);
+                    dfs.Compute();
+                }
+
+            }
+
+            var res = new List<PSDistanceVectorRecord>();
+            foreach (var record in distanceRecorder.Distances)
+            {
+                var rr = new PSDistanceVectorRecord() { Vertex = record.Key, Level = record.Value };
+                res.Add(rr);
+            }
+
+            WriteObject(res, enumerateCollection: true);
+        }
+    }
+}

PsGraph.Pester.Tests/PSGraph.GraphDistanceVector.Tests.ps1

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+BeforeAll {
+    Import-Module "/workspaces/PSGraph/PSGraph.Tests/bin/Debug/net8.0/PSQuickGraph.psd1"
+}
+
+Describe 'Get-GraphDistanceVector' {
+    BeforeEach {
+        # Initialize a new graph before each test
+        $graph = New-Graph
+
+        # Add vertices
+        Add-Vertex -Graph $graph -Vertex 'A'
+        Add-Vertex -Graph $graph -Vertex 'B'
+        Add-Vertex -Graph $graph -Vertex 'C'
+        Add-Vertex -Graph $graph -Vertex 'D'
+
+        # Add edges
+        Add-Edge -From 'A' -To 'B' -Graph $graph | Out-Null
+        Add-Edge -From 'A' -To 'C' -Graph $graph | Out-Null
+        Add-Edge -From 'B' -To 'D' -Graph $graph | Out-Null
+        Add-Edge -From 'C' -To 'D' -Graph $graph | Out-Null
+    }
+
+    It 'Should return the correct distance vector for the graph' {
+        # Run the Get-GraphDistanceVector cmdlet
+        $distanceVector = Get-GraphDistanceVector -Graph $graph
+
+        # Check the results are not empty
+        $distanceVector | Should -Not -BeNullOrEmpty
+
+        # Expected results for distance from root vertices
+        $expectedResults = @(
+            @{ Vertex = 'A'; Level = 0 },
+            @{ Vertex = 'B'; Level = 1 },
+            @{ Vertex = 'C'; Level = 1 },
+            @{ Vertex = 'D'; Level = 2 }
+        )
+
+        # Validate each record in the distance vector
+        foreach ($record in $distanceVector) {
+            $vertex = $record.Vertex.Name
+            $level = $record.Level
+
+            $expected = $expectedResults | Where-Object { $_.Vertex -eq $vertex }
+
+            $expected | Should -Not -BeNullOrEmpty
+            $level | Should -BeExactly $expected.Level
+        }
+    }
+
+    It 'Should return an empty result if the graph has no vertices' {
+        $emptyGraph = New-Graph
+        $result = Get-GraphDistanceVector -Graph $emptyGraph
+
+        # The result should be empty
+        $result | Should -BeNullOrEmpty
+    }
+}