PragmaticGP_pile6.feature

Feature: Uniform mutation works as specified
  In order to discover new beneficial variations of scripts that are already OK
  As a symbolic regression modeler
  I want uniform mutation to replace tokens in "parent" scripts with new random tokens

  
  Scenario: uniform mutation replaces tokens with uniform random sample of available tokens
    Given parent_1 is the Pile script "+ + + + + + + + + +"
    And the available tokens are ["a", "b", "c", "d", "e"]
    And the chance of mutation is p=1.0
    When I apply mutation to that parent (independently) many times
    Then the measured number of ["a", "b", "c", "d", "e"] in offspring should be statistically identical 
  
  Scenario: uniform mutation replaces randomly chosen tokens in the parent
    Given parent_1 is the Pile script "+ + + + + + + + + +"
    And the available tokens are ["a"]
    And the chance of mutation is p=0.5
    When I apply mutation to that parent (independently) many times
    Then the measured number of ["a", "+"] in offspring should be statistically identical 
  
  Scenario: uniform mutation conserves token count in offspring
    Given parent_1 is the Pile script "+ + + + + + + + + +"
    And the chance of mutation is p=1.0
    When I apply mutation to that parent (independently) many times
    Then there should be 10 tokens in every offspring