Small eigen collider


Published on

Published in: Technology
  • Be the first to comment

  • Be the first to like this

Small eigen collider

  1. 1. Small Eigen Collider Creating random ruby programs Andrew Grimm
  2. 2. Rationale ● Unit tests of existing projects failed on Rubinius because of bugs in things like String#split or StringIO#gets ● If I could generate random programs, I could see whether less popular implementations did the same thing as more popular implementations
  3. 3. Producing random code result = @receiver.send(@method, @parameter_objects, &:inspect) Where @receiver and @parameter_objects are randomly chosen objects, and @method is a randomly chosen method name.
  4. 4. Logging the results ● Currently printing the receiver, method, parameter objects and the result Receiver object: “a” Method: “casecmp” Parameters: [“b”] Result: -1
  5. 5. Comparing the results ● Run the script under different ruby versions ● Do a diff on the outputs
  6. 6. Example of a diff ● Lines above were running “a”.casecmp(“b”) diff MRI_output.txt rubinius_output.txt 180c180 < Result: -1 --- > Result: 1
  7. 7. Contents of the two files MRI_output.txt Receiver object: "a" Method: "casecmp" Parameters: ["b"] Result: -1 rubinius_output.txt Receiver object: “a” Method: “casecmp” Parameters: [“b”] Result: 1
  8. 8. Manual confirmation rvm ruby -e 'puts [RUBY_ENGINE, “a”.casecmp”b”].join(“t”) jruby -1 macruby -1 ruby -1 rbx 1 <= spot the odd one out
  9. 9. Protip ● Test the !@#$ing happy path! describe "String#casecmp" do it "is a case-insensitive version of String#<=>" do "abcdef".casecmp("abcde").should == 1 "aBcDeF".casecmp("abcdef").should == 0 "abcdef".casecmp("abcdefg").should == -1 "abcdef".casecmp("ABCDEF").should == 0 end # Snipped I18N tests end
  10. 10. Current tasks ● Make as safe as ruby allows (grain of salt here) ● Rather than randomly generating tasks each time, allow the tasks to be generated once, and run many times
  11. 11. Making the program safe Receiver object: nil Method: “system” Parameters: [“rm -rf /”] Result: :( ● Applying $SAFE to try to prevent bad things in a ruby-specific way ● Researching other sandboxing methods
  12. 12. Generate once, run many times ● Currently, I give all the rubies the same random number generator seed and same set of objects, and leave it up to them to choose which objects are in each task ● JRuby gives different random values than other platforms ● If the choice of tasks were made only once, then I could compare JRuby with others
  13. 13. Questions?