Merge pull request #36 from JuliaGraphs/fix-vertex-deletion

Fix vertex deletion

Author: bramtayl

docs/src/tutorial_basics.md

@@ -11,8 +11,8 @@ julia> using MetaGraphsNext
 We provide a default constructor in which you only need to specify types:
 
 ```jldoctest example
-julia> colors = MetaGraph( Graph(), VertexData = String, EdgeData = Symbol, graph_data = "graph_of_colors")
-Meta graph based on a Graphs.SimpleGraphs.SimpleGraph{Int64}(0, Vector{Int64}[]) with vertex labels of type Symbol, vertex metadata of type String, edge metadata of type Symbol, graph metadata given by "graph_of_colors", and default weight 1.0
+julia> colors = MetaGraph(Graph(), VertexData = String, EdgeData = Symbol, graph_data = "graph_of_colors")
+Meta graph based on a SimpleGraph{Int64}(0, Vector{Int64}[]) with vertex labels of type Symbol, vertex metadata of type String, edge metadata of type Symbol, graph metadata given by "graph_of_colors", and default weight 1.0
 ```
 
 ## Modifying the graph

src/graphs.jl

@@ -154,10 +154,10 @@ function _rem_vertex!(meta_graph::MetaGraph, label, code)
     removed = rem_vertex!(meta_graph.graph, code)
     if removed
         if code != last_vertex_code # ignore if we're removing the last vertex.
-            lastl = vertex_labels[last_vertex_code]
-            lastvprop = vertex_properties[lastl]
-            vertex_labels[code] = lastl
-            vertex_properties[lastl] = lastvprop
+            last_label = vertex_labels[last_vertex_code]
+            _, last_data = vertex_properties[last_label]
+            vertex_labels[code] = last_label
+            vertex_properties[last_label] = code, last_data
         end
         delete!(vertex_labels, last_vertex_code)
         delete!(vertex_properties, label)

test/runtests.jl

@@ -1,7 +1,26 @@
 using Documenter
 using MetaGraphsNext
 using Test
+using Graphs
 
 @testset "MetaGraphsNext" begin
     doctest(MetaGraphsNext)
+
+    colors = MetaGraph( Graph(), VertexData = String, EdgeData = Symbol, graph_data = "graph_of_colors")
+
+    labels = [:red, :yellow, :blue]
+    values = ["warm", "warm", "cool"]
+    for (label, value) in zip(labels, values)
+        colors[label] = value
+    end
+    for label in labels
+        @test label_for(colors, code_for(colors, label)) == label
+    end
+    #delete an entry and test again
+    rem_vertex!(colors, 1)
+    popfirst!(labels)
+    popfirst!(values)
+    for label in labels
+        @test label_for(colors, code_for(colors, label)) == label
+    end
 end