Make digraph base class immutable

Author: Kapil Borle

Engine/Helper.cs

@@ -3566,6 +3566,23 @@ public Digraph()
             graph = new List<List<int>> ();
         }
 
+        public Digraph(int numVertices, List<Tuple<int, int>> edges) : this()
+        {
+            for (int v = 0; v < numVertices; v++)
+            {
+                AddVertex();
+            }
+
+            foreach (Tuple<int, int> tuple in edges)
+            {
+                var fromV = tuple.Item1;
+                var toV = tuple.Item2;
+                ValidateVertex(fromV);
+                ValidateVertex(toV);
+                AddEdge(fromV, toV);
+            }
+        }
+
         public int GetNumVertices()
         {
             return graph.Count;
@@ -3587,12 +3604,12 @@ public bool ContainsVertex(int vertex)
             return vertex >= 0 && vertex < graph.Count;
         }
 
-        public void AddVertex()
+        protected void AddVertex()
         {
             graph.Add(new List<int>());
         }
 
-        public void AddEdge(int fromVertex, int toVertex)
+        protected void AddEdge(int fromVertex, int toVertex)
         {
             ValidateVertex(fromVertex);
             ValidateVertex(toVertex);

Tests/Engine/Helpers.tests.ps1

@@ -1,14 +1,17 @@
 Import-Module PSScriptAnalyzer
 
-Describe "Test Directed Graph" {
-    Context "When a graph is created" {
-        $digraph = New-Object -TypeName 'Microsoft.Windows.PowerShell.ScriptAnalyzer.DiGraph'
-        0..4 | ForEach-Object {$digraph.AddVertex()}
 
-        $digraph.AddEdge(0, 1);
-        $digraph.AddEdge(0, 4);
-        $digraph.AddEdge(1, 3);
+Function ConvertType($x)
+{
+    $z = [System.Collections.Generic.List[Tuple[int,int]]]::new()
+    $x | ForEach-Object {$z.Add([System.Tuple[int,int]]::new($_[0], $_[1]))}
+    return $z
+}
 
+Describe "Test Directed Graph" {
+    Context "When a graph is created" {
+        $edges = ConvertType (0,1),(0,4),(1,3)
+        $digraph = New-Object -TypeName 'Microsoft.Windows.PowerShell.ScriptAnalyzer.DiGraph' -ArgumentList 5,$edges
         It "correctly adds the vertices" {
             $digraph.GetNumVertices() | Should Be 5
         }