[QUIZ] Testing DiGraph (#73)
Ruby Quiz
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by Robert Feldt
In this week's Ruby Quiz you will not only have fun and (hopefully) learn
something; you will also contribute to a research project evaluating automated
testing techniques. So please read on and then take the quiz!
The goal of this quiz is to write a good and extensive test suite for a Ruby
DiGraph (directed graph) class. The new (hotshot, and annoying ;)) quality
manager at your work has challenged all the developers. He is planning major
cutbacks since he claims that automated testing tools can do as good or better a
job! The focus of the testing is on the following two methods of the DiGraph
class:
# Return the length of the longest simple path (an arc/edge can only
# occur once in the path) that includes <node>.
DiGraph#max_length_of_simple_path_including_node(node)
# Returns the strongly connected component (itself a DirectedGraph)
# that includes <node>.
DiGraph#strongly_connected_component_including_node(node)
Any Ruby object can be a node in a graph and you create graphs by giving a
number of edges. Each edge is an Array with maximum two nodes where the first
node is the source node.
The quiz has two phases: first a black-box phase and then a white-box phase. In
the black-box phase you do not have access to the source code but do your
testing over the network via drb. When you are satisfied with your tests for
this phase you submit them, get the source code and start the white-box phase.
Now you can extend your test suite given the actual code, fix problems and even
refactor the code as you see fit (as long as you do not change the interface).
You need to download the file "rubyquiz73.rb" to participate in the distributed
testing:
http://rubyquiz.com/rubyquiz73.rb
After downloading and saving that file, here is how you get a reference to the
class under test (CUT):
require 'test/unit'
require 'rubyquiz73'
# You must insert your email address as <youremail> in this method call!
DiGraph = RubyQuiz73.class_under_test("<youremail>")
class TestDiGraph < Test::Unit::TestCase
def test_01_digraph_creation
dg1 = DiGraph.new
assert_kind_of(DiGraph, dg1)
assert_equal(0, dg1.size)
end
def test_02_size
dg2 = DiGraph.new([1,2], [2,3])
assert_equal(3, dg2.size)
assert_equal(2, dg2.num_edges)
end
# Add/write your own tests here...
end
Note that since we use drb for the distributed testing and we had to make some
performance trade-offs not every assertion or code might work exactly as it
would if run locally. However, most "normal" things will work.
When you consider yourself ready with the blackbox phase of the testing you
should submit your test suite. You do this by issuing the command:
ruby rubyquiz73.rb submit1 <test_filename.rb>
and giving the path to your test file. The script will get back the source code
for the class being tested and save it. You can now look at the source code and
add tests as you see fit. You can also alter and refactor the source code as
long as you do not change the interface. When you are done with this, whitebox
phase, you submit your test file and source file like so (you can add additional
files if you have split your tests over several files):
ruby rubyquiz73.rb submit2 <test_filename.rb> <src_filename.rb>
[Editor's Note: Please also send in your tests to Ruby Talk, after the spoiler
period, for use in the summary. --JEG2]
You can also get some help information by issuing:
ruby rubyquiz73.rb help
You are encouraged to briefly document (in comments or by other means) how and
why you arrived at and included the test cases you've chosen and why you think
your tests are thorough. You are also encouraged to add tests for additional
methods of the DiGraph class as you see fit. Note that the devious Quality
Manager has not eliminated all problems with the given code so you are expected
to find problems/faults!
If the specifications in the RDoc comments above are not complete enough then
please make additional, sound assumptions and make them clear in your tests /
documentation.
http://www.cs.odu.edu/~toida/nerzic/content/digraph/definition.html
http://www.nist.gov/dads/HTML/stronglyConnectedCompo.html
James Edward Gray II
> by Robert Feldt
>
> In this week's Ruby Quiz you will not only have fun and (hopefully)
> learn
> something; you will also contribute to a research project
> evaluating automated
> testing techniques. So please read on and then take the quiz!
No takers on this one? You guys obviously have no idea how much
effort Robert put into setting this up... :(
James Edward Gray II
Kev Jackson
I've just tried it, but I'm getting problems with my email
@it.fts-vn.com - the '-' isn't recognized in the self.valid_email?
method, small alteration to regexp fixed that, now I have firewall
issues here - off to speak to the network people.... I'm suprised too.
Normally I get in after the weekend and browse through everyones
solutions to learn more ruby, but this Monday, nothing.
Still I'll give it a try and see what I can do (probably not a lot,
still learning ruby)
Kev
Matthew Moss
Apologies... Maybe it was the density of the problem (or the density
of my head), but I really didn't have a clue as to what was being
asked. And as I usually avoid the longer ruby quizzes due to time, I
made no attempt.
Himadri Choudhury
>> dg2 = DiGraph.new([1,2], [2,3])
If I try to pass an array of arrays to new, it doesn't work.
Is there a way to use reflection to figure this out?
Lutz Horn
* Kev Jackson:
> I've just tried it, but I'm getting problems with my email
> @it.fts-vn.com - the '-' isn't recognized in the self.valid_email?
> method, small alteration to regexp fixed that,
Same here. '-' should be included in the email regexp.
> now I have firewall
> issues here - off to speak to the network people.... I'm suprised too.
Dito, the message being:
Could not connect to druby://pronovomundo.com:2000
Could not connect to druby://aquas.htu.se:8954
And there is no way to open these ports in the firewall :(
Sorry, but I can't work on this interesting problem.
Regards
Robert Feldt
> Hi,
>
> * Kev Jackson:
> > I've just tried it, but I'm getting problems with my email
> > @it.fts-vn.com - the '-' isn't recognized in the self.valid_email?
> > method, small alteration to regexp fixed that,
>
> Same here. '-' should be included in the email regexp.
>
> > now I have firewall
> > issues here - off to speak to the network people.... I'm suprised too.
>
> Dito, the message being:
>
> Could not connect to druby://pronovomundo.com:2000
> Could not connect to druby://aquas.htu.se:8954
>
> And there is no way to open these ports in the firewall :(
>
> Sorry, but I can't work on this interesting problem.
>
If I can find a server were I can use port 80 it should work for you?
If so I'll try to set it up. I'm in academia where these things tends
to be less controlled so I didn't think about the common situation
when in the commercial world... ;)
If there is enough interest I would like to extend this quiz so that
more people can make a stab at it before we summarize.
Regards,
Robert Feldt
Robert Dober
box phase.
Just could not get the time assigned to.
Really sorry for Robert that nobody had, but maybe this weekend?
Cheers
Robert
--
Deux choses sont infinies : l'univers et la bêtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.
- Albert Einstein
Robert Feldt
> I got through the black box phase, but I did not make it through the white
> box phase.
> Just could not get the time assigned to.
"small" example to keep the time down but it has to have at least the
potential for some interesting quirks/situations and thus cannot be
too simple or trivial. It is a hard balance to strike.
> Really sorry for Robert that nobody had, but maybe this weekend?
>
I sure hope so; the servers will keep running and I'll try to migrate
one of them to port 80.
Regards,
Robert Feldt
Himadri Choudhury
collection of paths to create a DiGraph?
Robert Feldt
> Perhaps I can ask this in another way. Is it possible to pass a variable
> collection of paths to create a DiGraph?
>
DiGraph.new([1,2]) create a DiGraph like so
1 -> 2
and DiGraph.new([1,2], [2,3]) creates a DiGraph like so
1 -> 2 -> 3
Does this help?
Regards,
Robert
Himadri Choudhury
I wanted to be able to pass an array of edges, so that the array can be
generated programmatically.
Robert Feldt
> Then you have to manually enter all the edges?
> I wanted to be able to pass an array of edges, so that the array can be
> generated programmatically.
>
def m(*a)
p a
end
m(1, 2) # => [1,2]
a = [3,4]
m(*a) # => [3,4]
Best Regards,
Robert
Paul Novak
the problem domain, if it is new to you. I second the idea of extending
this quiz.
Regards,
Paul.
On 4/4/06, Robert Feldt <robert...@gmail.com> wrote:
>
James Edward Gray II
> When you consider yourself ready with the blackbox phase of the
> testing you
> should submit your test suite. You do this by issuing the command:
>
> ruby rubyquiz73.rb submit1 <test_filename.rb>
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("ja...@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))
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
James Edward Gray II
> This is a very interesting quiz, but it takes some time just to
> understand
> the problem domain, if it is new to you. I second the idea of
> extending
> this quiz.
Alright, we will extend the quiz one week.
I expect to see your solution Paul. A little bird tells me that you
lead Ruby Quiz discussions for your local Ruby brigade, so you are
now officially all out of good excuses not to submit... ;)
James Edward Gray II
James Edward Gray II
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
Kev Jackson
>
> # 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
>
not understanding the concepts of digraph (so back to the web to check
my knowledge), or was it one of those bugs referred to in the quiz...?
Nice to know that someone else thought that this was a bug - I couldn't
get why 1=>2=>1 would have 6 edges/vertices :)
Thanks for posting the black box stuff James, I've been wondering about
those 6 vertices since yesterday!
Kev
Himadri Choudhury
Files:
rubyquiz73_test_bbox.rb - black box test
rubyquiz73_test_wbox.rb - white box test
digraph.rb - modified source code
Basically I tried to create digraphs is a somewhat automated and random way using the function 'generate_dg'
This function generates a dg in @dg, an array of nodes in @nodes, and an adjacency hash in @paths.
In the adjacency hash, called @paths, @path[X] is an array of all the nodes coming out of node X.
The functions test_03 and test_04 attempt to test the max_length_of_simple_path_including_node and strongly_connected_component_including_node functions. I created a 'reference' model for these functions to test against.
During whitebox testing I created a few additional tests to test cases where I found bugs.
Thanks for the interesting problem.
From my earlier post I think you can tell I'm pretty new to ruby.
I really learned a lot, especially by looking at the source code for digraph
Himadri