spec/graph/edge_spec.rb

   1 require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
   2
   3 module GraphNjae
   4   describe Edge do
   5     let (:e) { Edge.new }
   6     let(:v1) {Vertex.new :name => :v1}
   7     let(:v2) {Vertex.new :name => :v2}
   8     let(:v3) {Vertex.new :name => :v3}
   9
  10     describe "#initialize" do
  11       it "creates an empty edge" do
  12         e = Edge.new
  13         e.connections.should be_empty
  14       end
  15
  16       it "creates an edge with some parameters" do
  17         e = Edge.new :value1 => 1, :value2 => "value2", :value3 => :v3
  18         e.value1.should == 1
  19         e.value2.should == "value2"
  20         e.value3.should == :v3
  21         e.value4.should be_nil
  22       end
  23     end # #initialize
  24
  25     describe "adds attribues" do
  26       it "adds then reports arbitrary attributes" do
  27         e.score = 15
  28         e.score.should == 15
  29       end
  30     end # adds attributes
  31
  32     describe "#<<" do
  33       it "adds a new vertex to an edge (with a connection)" do
  34         e.connections.should be_empty
  35         e << v1
  36         e.should have(1).connections
  37         e.should have(1).vertices
  38         e.vertices.should include(v1)
  39         v1.edges.should include(e)
  40         e << v2
  41         e.should have(2).connections
  42         e.should have(2).vertices
  43         e.vertices.should include(v1)
  44         e.vertices.should include(v2)
  45         v2.edges.should include(e)
  46       end
  47
  48       it "adds several vertices to an edge" do
  49         e.connections.should be_empty
  50         e << v1 << v2
  51         e.vertices.should include(v1)
  52         e.vertices.should include(v2)
  53         e.should have(2).vertices
  54       end
  55
  56       it "adds a self-loop" do
  57         e.connections.should be_empty
  58         e << v1 << v1
  59         e.vertices.should include(v1)
  60         e.should have(2).vertices
  61         e.vertices.uniq.length.should == 1
  62       end
  63     end # #<<
  64
  65     describe "connection_at" do
  66       it "returns the connection that links to a vertex" do
  67         e.connections.should be_empty
  68         e << v1 << v2
  69
  70         e.connection_at(v1).end.should be v1
  71         e.connection_at(v2).end.should be v2
  72       end
  73
  74       it "returns nil if there is no connection to that vertex" do
  75         e.connections.should be_empty
  76         e << v1 << v2
  77
  78         e.connection_at(v3).should be nil
  79       end
  80
  81       it "returns the vertex for a self-loop" do
  82         e.connections.should be_empty
  83         e << v1 << v1
  84
  85         e.connection_at(v1).end.should be v1
  86       end
  87     end # #connection_at
  88
  89     describe "other_end" do
  90       it "returns the vertex at the other end of the given one" do
  91         e.connections.should be_empty
  92         e << v1 << v2
  93
  94         e.other_end(v1).should be v2
  95         e.other_end(v2).should be v1
  96       end
  97
  98       it "returns the same vertex in a self-loop" do
  99         e.connections.should be_empty
 100         e << v1 << v1
 101
 102         e.other_end(v1).should be v1
 103       end
 104
 105       it "returns one of the connected edges if given a vertex not connected to it" do
 106         e.connections.should be_empty
 107         e << v1 << v2
 108
 109         [v1, v2].should include e.other_end(v3)
 110       end
 111
 112       it "returns nil if it can't return something sensible" do
 113         e.other_end(v1).should be_nil
 114         e << v1
 115         e.other_end(v1).should be_nil
 116       end
 117     end # other_end
 118
 119     describe "#to_dot" do
 120       it "describes an edge in dot notation" do
 121         e << v1 << v2
 122
 123         e.to_dot.should == "#{v1.object_id.to_s} -- #{v2.object_id.to_s};"
 124       end
 125
 126       it "describes an edge in dot notation, using given attributes" do
 127         e << v1 << v2
 128         #vdot = v1.to_dot :label => :name, :shape => :shape
 129         #vdot.should == "#{v.object_id.to_s} {label = \"vertex\", shape = \"house\"};"
 130       end
 131
 132
 133       it "describes an edge in dot notation, given a block" do
 134         e << v1 << v2
 135
 136         e.to_dot {|e| e.object_id.to_s}.should == e.object_id.to_s
 137       end
 138     end # dot
 139   end # Edge
 140
 141   describe Connection do
 142     let (:c) {Connection.new }
 143
 144     describe "adds attribues" do
 145       it "adds then reports arbitrary attributes" do
 146         c.score = 15
 147         c.score.should == 15
 148       end
 149     end # adds attributes
 150   end # Connection
 151
 152 end