Class: Toaster::StateTransitionGraph

Inherits:
Object
  • Object
show all
Defined in:
lib/toaster/state/state_transition_graph.rb

Constant Summary collapse

META_PROPERTIES = 
["__task_num__", "__original__", "__combo__"]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ StateTransitionGraph

Returns a new instance of StateTransitionGraph.



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# File 'lib/toaster/state/state_transition_graph.rb', line 25

def initialize 
  @start_node = StateNodeInitial.new
  @end_node = StateNodeFinal.new
  @tasks = []
  @ignore_properties = []
  @task_executions = {}
  # set of all nodes
  @nodes = Set.new
  # set of nodes without start nodes and end nodes
  @nodes_without_terminals = Set.new
  # set of all edges
  @edges = Set.new
  # set of edges which connect "actual" state nodes, i.e.,
  # not including edges containing a start node or end node
  @edges_without_terminal_nodes = Set.new
  # avoid circles in the generated graph..?
  @avoid_circles = false
end

Instance Attribute Details

#avoid_circles ⇒ Object

Returns the value of attribute avoid_circles.



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# File 'lib/toaster/state/state_transition_graph.rb', line 21

def avoid_circles
  @avoid_circles
end

#edges(include_start_and_end_nodes = false) ⇒ Object (readonly)

Returns the value of attribute edges.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def edges
  @edges
end

#end_node ⇒ Object (readonly)

Returns the value of attribute end_node.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def end_node
  @end_node
end

#ignore_properties ⇒ Object (readonly)

Returns the value of attribute ignore_properties.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def ignore_properties
  @ignore_properties
end

#nodes(include_terminal_nodes = false) ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def nodes
  @nodes
end

#start_node ⇒ Object (readonly)

Returns the value of attribute start_node.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def start_node
  @start_node
end

#task_executions ⇒ Object (readonly)

Returns the value of attribute task_executions.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def task_executions
  @task_executions
end

#tasks ⇒ Object (readonly)

Returns the value of attribute tasks.



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# File 'lib/toaster/state/state_transition_graph.rb', line 19

def tasks
  @tasks
end

Class Method Details

.build_graph_for_automation(automation, coverage_goal = nil) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 93

def self.build_graph_for_automation(automation, coverage_goal=nil)
  coverage_goal = TestCoverageGoal.new if !coverage_goal

  if !automation
    raise "Cannot build graph for nil automation."
  end

  ignore_properties = []
  # dup here to avoid updates of active record
  ignore_properties.concat(automation.ignore_properties.to_a.dup)
  additional_ignores = SystemState.read_ignore_properties()
  additional_ignores = [] if !additional_ignores
  ignore_properties.concat(additional_ignores)
  puts "DEBUG: ignore_properties: #{ignore_properties}"

  # list of tasks
  TimeStamp.add(nil, "get_tasks")
  tasks = automation.get_globally_executed_tasks
  TimeStamp.add_and_print("load automation tasks", nil, "get_tasks")
  # let's make sure the list of tasks is index-based (i.e., not a Set)
  # (because we want to do index-based lookaheads in the tasks array later on..)
  tasks = tasks.to_a
  # STG instance
  graph = build_graph_for_tasks(tasks, coverage_goal, ignore_properties)

  return graph
end

.build_graph_for_tasks(tasks, coverage_goal = nil, ignore_properties = []) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 121

def self.build_graph_for_tasks(tasks, coverage_goal=nil, ignore_properties=[])
  coverage_goal = TestCoverageGoal.new if !coverage_goal

  TimeStamp.add(nil, "build_graph")
  graph = StateTransitionGraph.new()
  graph.avoid_circles = coverage_goal.repeat_N.to_i >= 0
  graph.ignore_properties.concat(ignore_properties)
  graph.tasks.concat(tasks)
  tasks.each do |t|
    t.global_executions.each do |exe|
      if exe.success
        graph.task_executions[t] = [] if !graph.task_executions[t]
        graph.task_executions[t] << exe
      end
    end
  end
  TimeStamp.add_and_print("load task executions for list of #{tasks.size} tasks.", nil, "build_graph")

  TimeStamp.add(nil, "build_graph_states")
  graph.build_states_for_task_executions()
  TimeStamp.add_and_print("build states from task executions", nil, "build_graph_states")

  idem_numtasks = coverage_goal.idempotence
  if idem_numtasks
    idem_numtasks = [idem_numtasks] if !idem_numtasks.kind_of?(Array)
    TimeStamp.add(nil, "extend_idem")
    idem_numtasks.each do |idem|
      if tasks.size >= idem
        graph.extend_for_idempodence(idem, coverage_goal.only_connect_to_start)
      end
    end
    TimeStamp.add_and_print("extend graph for idempotence", nil, "extend_idem")
  end

  TimeStamp.add(nil, "extend_comb")
  coverage_goal.combinations.each do |type,lengths|
    if type == CombinationCoverage::COMBINE_N
      lengths.each do |n|
        graph.extend_for_combinations(n, false)
      end
    elsif type == CombinationCoverage::COMBINE_N_SUCCESSIVE
      lengths.each do |n|
        graph.extend_for_combinations(n, true)
      end
    elsif type == CombinationCoverage::SKIP_N
      lengths.each do |n|
        graph.extend_for_skippings(n, false)
      end
    elsif type == CombinationCoverage::SKIP_N_SUCCESSIVE
      lengths.each do |n|
        graph.extend_for_skippings(n, true)
      end
    end
  end
  TimeStamp.add_and_print("extend graph for combinations", nil, "extend_comb")

  return graph
end

.build_graph_for_test_suite(test_suite) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 89

def self.build_graph_for_test_suite(test_suite)
  return build_graph_for_automation(test_suite.automation, test_suite.coverage_goal)
end

Instance Method Details

#add_state(state_props) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 82

def add_state(state_props)
  n = StateNode.new(state_props)
  @nodes.add(n)
  @nodes_without_terminals.add(n)
  return n
end

#build_states_for_task_executions(insert_nil_prestate_prop_for_insertions = false) ⇒ Object

Build the basic graph nodes as a permutation over the pre-states and post-states of task executions monitored by the system.



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# File 'lib/toaster/state/state_transition_graph.rb', line 185

def build_states_for_task_executions(insert_nil_prestate_prop_for_insertions=false)

  # node front, i.e., list of temporary child nodes as 
  # we iterate through the tasks and build the graph
  node_front = [start_node()]

  count = 0

  puts "INFO: Building graph states for #{tasks.size} tasks."

  # nested loop 1
  tasks.each do |t|
    count += 1

    #puts "INFO: Handling task ##{count} of #{tasks.size}. Node front size: #{node_front.size}"

    execs = task_executions[t]

    # initialize the hash with a single element that 
    # represents an "empty pre-state" with an "empty set of conditions". 
    # This makes sure that we always execute the innermost
    # loop at least once, which is actually only relevant
    # for the last task which has no "next pre-states"...
    trans_next_desired_pre_states = {
                              {} => Set.new
                            }

    # make a look-ahead to the pre-states of the next task in our sequence
    if count < tasks.size
      t_next = tasks[count]
      execs_next = task_executions[t_next]
      transitions_next = t_next.global_state_transitions(execs_next, insert_nil_prestate_prop_for_insertions)
      # insert artificial transition, for automations which have not been executed before
      if transitions_next.empty?
        transitions_next << StateTransition.new
      end
      trans_next_desired_pre_states = StateTransitionGraph.prestates_from_transitions(transitions_next)
    end
    #puts "trans_next_desired_pre_states size: #{trans_next_desired_pre_states.size}"

    transitions = t.global_state_transitions(execs, insert_nil_prestate_prop_for_insertions)
    # insert artificial transition, for automations which have not been executed before
    if transitions.empty?
      transitions << StateTransition.new
    end
    prestates = t.global_pre_states_reduced(transitions)
    desired_prestates_in_tests = prestates

    log "desired_prestates_in_tests #{desired_prestates_in_tests.inspect}"

    # are we handling the first task?
    if count == 1
      desired_prestates_in_tests.each do |pre|
        # remove ignored properties
        remove_ignore_props(pre)
        # artificially introduce __task_num__ parameter, because
        # we want to obtain a nice, cycle-free "left-to-right" 
        # graph that grows as we iterate through the tasks
        n = get_state(pre.merge({"__task_num__" => count-1, "__original__" => true}))
        n.succeeding_task = t
        connect(start_node, n)
        node_front << n
      end
      node_front.delete(start_node())
    end

    # copy and clear node front list
    node_front_copy = node_front
    node_front = []

    trans_post_states = StateTransitionGraph.poststates_from_transitions(transitions)

    # nested loop 2
    trans_post_states.each do |post,trans_conditions|

      # Since post states are determined from the state changes
      # of state transitions, we might get into a situation where 
      # the repeated execution of a task (because we test idempotence) 
      # does not result in any state changes and hence we receive an
      # empty post state... 
      # This would be incorrect and would blow up our STG!
      # Hence, we only continue here if either
      # - the post state is not empty, OR
      # - there is only one (probably empty) post state
      if !post.empty? || trans_post_states.size == 1

        # remove ignored properties
        remove_ignore_props(post)

        # nested loop 3
        node_front_copy.each do |node|

          # nested loop 4
          trans_next_desired_pre_states.each do |pre_next,trans_conditions_next|

            new_state = {}
            StateTransitionGraph.state_merge!(new_state, node.properties)
            StateTransitionGraph.state_merge!(new_state, pre_next)
            StateTransitionGraph.state_merge!(new_state, post)
            # again, additionally introduce __task_num__ parameter
            StateTransitionGraph.state_merge!(new_state, {"__task_num__" => count, "__original__" => true})

            n = get_state(new_state)

            n.preceding_task = t
            if count < tasks.size
              n.succeeding_task = tasks[count]
            end

            connect(node, n, trans_conditions)
            if !node_front.include?(n) && StateTransitionGraph.node_satisfies_poststate(n, post)
              node_front << n
            end

          end

        end

      end

    end

    # are we handling the last task?
    if count >= tasks.size
      node_front.each do |n|
        connect(n, end_node())
      end
    end

  end

  return self
end

#connect(node1, node2, conditions = nil, transition = nil) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 44

def connect(node1, node2, conditions=nil, transition=nil)
  edge = TransitionEdge.new(node1, node2, conditions, transition)
  @edges.add(edge)
  if node1.succeeding_task
    @edges_without_terminal_nodes.add(edge)
  end
  node1.outgoing.add(edge)
  node2.incoming.add(edge)
end

#connect_to_matching_prestate(node, num_tasks_back) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 349

def connect_to_matching_prestate(node, num_tasks_back)
  preceding_task = get_preceding_task(node, num_tasks_back)
  
  if preceding_task

    prestate_node = nil

    if !@avoid_circles
      # find non-conflicting pre-state for this post-state
      prestates = prestate_nodes_of_task(preceding_task)
      non_conflicting_node = nil
      prestates.each do |pre|
        if !pre.conflicts_with?(node, META_PROPERTIES)
          non_conflicting_node = pre
          break
        end
      end
      prestate_node = non_conflicting_node
    else
      # always create a new state node
      prestate_node = nil
    end

    is_new_node = false
    if !prestate_node
      state_props = node.properties.dup
      # decrease property "__task_num__"
      state_props["__task_num__"] -= num_tasks_back + 1
      # remove property "__original__"
      state_props.delete("__original__")
      prestate_node = add_state(state_props)
      prestate_node.succeeding_task = preceding_task
      prestate_node.preceding_task = nil
      is_new_node = true
      #connect_to_prestate_recursively(new_node)
    end

    #connect node to new node
    connect(node, prestate_node, nil)

    # connect new node to successor node (recursively)
    if is_new_node
      connect_to_successor_recursive(prestate_node) 
    end
    #end

  else
    # connect to start_node
    # TODO needed?
    #connect(@start_node, node, nil)
  end

end

#connect_to_successor_recursive(node, consider_task_convergence = false) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 403

def connect_to_successor_recursive(node, consider_task_convergence=false)
  next_task = node.succeeding_task
  # find non-conflicting pre-state of the next task
  states = poststate_nodes_of_task(next_task)
  non_conflicting_node = nil
  if !@avoid_circles
    states.each do |state|
      if !state.conflicts_with?(node, META_PROPERTIES)
        non_conflicting_node = state
        break
      end
    end
  end
  # connect to new node
  if non_conflicting_node
    connect(node, non_conflicting_node)
  else
    state_props = node.properties.dup
    # increase property "__task_num__" by 1
    state_props["__task_num__"] += 1
    # remove property "__original__"
    state_props.delete("__original__")

    if consider_task_convergence
      # TODO needed?
      raise "not implemented"
      # add properties which represent the state change of the task execution
      #execs = task_executions[next_task]
      #transitions = next_task.global_state_transitions(execs)
      #poststates = next_task.global_post_states_reduced(transitions)
      #state_props.merge!(poststates)
    end

    new_node = add_state(state_props)
    new_node.preceding_task = node.succeeding_task
    new_node.succeeding_task = get_task_after(node.succeeding_task)
    #connect node to new node
    connect(node, new_node)

    if new_node.succeeding_task
      connect_to_successor_recursive(new_node)
    else
      connect(new_node, @end_node)
    end
  end
end

#extend_for_combination_set(combinations) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 469

def extend_for_combination_set(combinations)

  combinations.each do |combo|

    node_front = [start_node]
    
    combo_id = Util.generate_short_uid()

    combo.each do |task|

      node_front_copy = node_front.dup
      node_front = []

      node_front_copy.each do |node|

        task_prestates = prestate_nodes_of_task_reachable_from_node(task, node)

        task_prestates.each do |prestate_node|

          prestate_node_copy = prestate_node

          if combo.index(task) <= 0
            prestate_node = get_state(prestate_node.properties.merge("__combo__" => combo_id))
          elsif combo.index(task) >= combo.size - 1
            node = get_state(node.properties.merge("__combo__" => combo_id))
          else
            node = get_state(node.properties.merge("__combo__" => combo_id))
            prestate_node = get_state(prestate_node.properties.merge("__combo__" => combo_id))
          end

          connect(node, prestate_node, nil)
          node_front << prestate_node_copy

        end
      end

    end

    # finally, connect all nodes in the "node front" to the end node
    node_front.each do |node|
      connect(node, @end_node, nil)
    end

  end

end

#extend_for_combinations(combination_length, successive = false) ⇒ Object

Add graph nodes and edges to satisfy different task combination test coverage criteria. Args:

- *combination_length*: length of the task combinations to be covered.
- *only_successive*: whether the combinations have to be successive tasks.



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# File 'lib/toaster/state/state_transition_graph.rb', line 457

def extend_for_combinations(combination_length, successive=false)
  #puts "INFO generating combinations of length #{combination_length} for list with #{tasks.size} tasks, only_successive=#{successive}"
  combinations = Combinatorial.combine(tasks, combination_length, successive)
  extend_for_combination_set(combinations)
end

#extend_for_idempodence(num_tasks, only_connect_to_start = true) ⇒ Object

Add graph nodes and edges to satisfy the idempotence test coverage criterion for a given number of tasks.



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# File 'lib/toaster/state/state_transition_graph.rb', line 324

def extend_for_idempodence(num_tasks, only_connect_to_start=true)

  nodes_before = @nodes_without_terminals.size
  puts "DEBUG: Extending graph with #{nodes_before} nodes " +
    "for idempotence of length=#{num_tasks}, only_connect_to_start=#{only_connect_to_start}"
  @nodes_without_terminals.dup.each do |n|
    if original_node?(n)
      if n.succeeding_task
        task_index = tasks.index(n.succeeding_task)
        if !only_connect_to_start || task_index == num_tasks
          connect_to_matching_prestate(n, num_tasks - 1)
        end
      else
        task_index = tasks.index(n.preceding_task) + 1
        if !only_connect_to_start || task_index == num_tasks
          #puts "DEBUG: Connecting node #{n} to matching prestate, num_tasks=#{num_tasks}"
          connect_to_matching_prestate(n, num_tasks - 1)
        end
      end
    end
  end
  nodes_after = @nodes_without_terminals.size

end

#extend_for_skippings(combination_length, successive = false) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 463

def extend_for_skippings(combination_length, successive=false)
  #puts "INFO generating 'skippings' of length #{combination_length} for list with #{tasks.size} tasks, only_successive=#{successive}"
  combinations = Combinatorial.skip(tasks, combination_length, successive)
  extend_for_combination_set(combinations)
end

#get_state(state_props) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 64

def get_state(state_props)
  return nil if !state_props
  # remove ignored properties from map
  remove_ignore_props(state_props)
  hash_code = state_props.hash
  # search for existing node
  @nodes_without_terminals.each do |n|
    # first compare hash code
    if hash_code == n.properties.hash
      # now compare actual properties
      if n.properties.eql?(state_props)
        return n
      end
    end
  end
  return add_state(state_props)
end

#to_simple_json(include_start_and_end_nodes = true) ⇒ Object 



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# File 'lib/toaster/state/state_transition_graph.rb', line 516

def to_simple_json(include_start_and_end_nodes=true)

  if @nodes.size > 1000
    puts "WARN: Graph contains #{@nodes.size} nodes. Aborting request."
    return "{}"
  end

  json = {}
  nodes = (json["nodes"] = [])
  edges = (json["edges"] = [])
  node_ids = {}
  if include_start_and_end_nodes
    node_ids[@start_node] = "__start__"
    node_ids[@end_node] = "__end__"
    nodes << { "ID" => "__start__", "name" => "Start", "column" => 1, "content" => "" }
    nodes << { "ID" => "__end__", "name" => "End", "column" => @tasks.size + 3, "content" => "" }
  end
  counter = 0
  # build list of nodes
  @nodes.each do |n|
    counter += 1
    node_ids[n] = "n#{counter}"
    props = n.properties.dup
    task_num = props["__task_num__"]
    META_PROPERTIES.each do |mp|
      props.delete(mp)
    end
    name = "State #{counter}"
    content = MarkupUtil.to_pretty_json(props)[1..-2].strip
    nodes << { "ID" => node_ids[n], 
        "name" => name,
        "content" => content,
        "column" => task_num + 2
      }
  end
  # build list of edges
  nodes_with_start = @nodes_without_terminals.dup
  nodes_with_start << @start_node
  nodes_with_start.each do |n|
    n.outgoing.each do |e|
      from = node_ids[e.node_from]
      to = node_ids[e.node_to]
      if from && to
        task = e.represented_task
        link = $cgi && task ? l('auto' => '', 'task' => task.id, 't' => 'tasks') : ""
        label = task ? task.name : ""
        label_short = task ? ("t#{@tasks.index(task) + 1}") : ""
        edges << { "from" => from, "to" => to, "href" => link,
                   "label" => label, "label_short" => label_short }
      end
    end
  end
  return MarkupUtil.to_pretty_json(json)
end