```On Apr 4, 2006, at 12:24 PM, James Edward Gray II wrote:

> For this phase, I decided to just try some common sense tests and
> stop whenever something that looked like a bug.  Here's my set of
> tests so far:
>
> require 'test/unit'
> require 'rubyquiz73'
>
> DiGraph = RubyQuiz73.class_under_test("james / grayproductions.net")
>
> class TestDiGraph < Test::Unit::TestCase
>   def test_construction
>     graph = nil
>     assert_nothing_raised(Exception) { graph = DiGraph.new }
>     assert_not_nil(graph)
>     assert_kind_of(DiGraph, graph)
>
>     assert_nothing_raised(Exception) do
>       graph = DiGraph.new(Array.new(rand(10)) { |i| [i * 2, i * 2 +
> 1] })
>     end
>     assert_not_nil(graph)
>     assert_kind_of(DiGraph, graph)
>   end
>
>   def test_size
>     graph = DiGraph.new
>     assert_equal(0, graph.size)
>     assert_equal(0, graph.num_edges)
>
>     graph = DiGraph.new([1,2], [2,3])
>     assert_equal(3, graph.size)
>     assert_equal(2, graph.num_edges)
>
>     graph = DiGraph.new([1,2], [2,3], [3, 2])
>     assert_equal(3, graph.size)
>     assert_equal(3, graph.num_edges)
>   end
>
>   def test_max_length_of_simple_path_including_node
>     10.times do |count|
>       graph_straight_line(count)
>       assert_equal(count, @graph.num_edges)
>       0.upto(count) do |i|
>         assert_equal(count,
> @graph.max_length_of_simple_path_including_node(i))

The above line has an error in it.  Since I am creating one-way paths
here the assertion should be:

assert_equal(count - i, ... )

After seeing the code, I found this and other bugs.

James Edward Gray II

>       end
>     end
>
>     # BUG:  [0, 1], [1, 0] => 6  # there are only two edges
> #     10.times do |count|
> #       graph_down_and_back(count)
> #       assert_equal(count * 2, @graph.num_edges)
> #       0.upto(count) do |i|
> #         assert_equal( @graph.num_edges,
> #
> @graph.max_length_of_simple_path_including_node(i) )
> #       end
> #     end
>   end
>
>   def test_strongly_connected_component_including_node
>     10.times do |count|
>       graph_down_and_back(count)
>       0.upto(count) do |i|
>         scc = @graph.strongly_connected_component_including_node(i)
>         assert_equal(@graph.size, scc.size)
>         assert_equal(@graph.num_edges, scc.num_edges)
>       end
>     end
>
>     # BUG:  [0, 1], [1, 2] => [0, 1], [1, 2]  # one-way is not a
> strong connect
> #     10.times do |count|
> #       graph_straight_line(count)
> #       0.upto(count) do |i|
> #         scc = @graph.strongly_connected_component_including_node(i)
> #         assert_equal(count.zero? ? 0 : 1, scc.size)
> #         assert_equal(0, scc.num_edges)
> #       end
> #     end
>   end
>
>   private
>
>   def straight_line( size )
>     Array.new(size) { |i| [i, i + 1] }
>   end
>
>   def graph_straight_line( size )
>     @graph = DiGraph.new(*straight_line(size))
>   end
>
>   def graph_down_and_back( size )
>     data = straight_line(size)
>     @graph = DiGraph.new(*(data + data.reverse.map { |edge|
> edge.reverse }))
>   end
> end
>
> __END__
>
> James Edward Gray II
>
>

```