rdingus.rb

require 'rubygems'
require 'spec'

if not defined? BlankSlate
  class BlankSlate
    instance_methods.each { |m| undef_method m unless m =~ /^(__|instance_eval)/ }
  end
end

class RDingus < BlankSlate
  def initialize(parent = nil, invocation = nil)
    @parent = parent
    @invocation = invocation
    @invocations = InvocationList.new
    @invocation_expectations = InvocationResultHash.new
    @children = []
    @call_count = 0
  end

  def method_missing(name, *args, &block)
    @call_count += 1
    invocation = InvocationRecord.new(self, name, args)
    @invocations << invocation

    if @invocation_expectations.defined?(invocation)
      result = @invocation_expectations[invocation]
      begin
        if result._dingus?
          result
        end
      rescue NoMethodError
        # We use this kludge, because it's the only way to test for a dingus
        # We need to know it's not a dingus before calling other methods
        if result.is_a?(Proc)
          obj = Object.new
          obj.extend(DingusProc)
          obj.args = args
          obj.method = name
          obj.block = block
          obj.instance_eval &result
        else
          result
        end
      end
    else
      dingus = RDingus.new(self, invocation)
      @children << dingus
      @invocation_expectations[invocation] = dingus
    end
  end

  def _define(&block)
    proxy = DefinitionProxy.new(self, @invocation_expectations)

    if block
      proxy.instance_eval &block
    else
      proxy
    end
  end

  def _calls
    @invocations
  end

  def _dingus?
    true
  end

  def inspect
    "#<RDingus #{__id__}, calls=#{@call_count}>"
  end

  def dup
    self
  end

  def clone
    dup
  end

public

  module DingusProc
    attr_accessor :method, :args, :block
  end

  class DefinitionProxy < BlankSlate
    def initialize(parent = nil, list = nil)
      @parent = parent
      @list = list || InvocationResultHash.new
    end

    def method_missing(m, *args, &block)
      if block
        invocation = InvocationRecord.new(@parent, m, args, block)
        @list[invocation] = block
      else
        if args.empty?
          invocation = InvocationRecord.new(@parent, m, args)
          dingus = RDingus.new(@parent, invocation)
          @list[invocation] = dingus
          dingus._define
        else
          invocation = InvocationRecord.new(@parent, m, [], args.first)
          @list[invocation] = args.first
        end
      end
    end

    def _define(&block)
      self.instance_eval &block
    end

    def _list
      @list
    end
  end

  class InvocationRecord
    attr_reader   :dingus, :method, :args
    attr_accessor :value

    def initialize(dingus, method, args = [], *optional)
      @dingus = dingus
      @method = method
      @args = args
      @value = optional.first
      @has_value = !optional.empty?
    end

    def value=(v)
      @has_value = true
      @value = v
    end

    def has_value?
      @has_value
    end

    def eql?(b)
      self.method == b.method && ((self.args == b.args) || self.any? || b.any?)
    end

    def ==(b)
      self.eql?(b)
    end

    def any?
      @args && @args.first == :any
    end

    def to_s
      "#{method}(#{args.map{|i|i.inspect}.join(", ")})"
    end

    def inspect
      retval = @has_value ? " => #{@value.inspect}" : ""
      "#<Invocation \"#{self}\"#{retval}>"
    end

  end

  class InvocationResultHash
    def initialize
      @list = []
    end

    def []=(invocation, value)
      @list << [invocation, value]
      value
    end

    def [](invocation)
      @list.reverse.each do |inv, value|
        return value if inv == invocation
      end
      nil
    end

    def defined?(invocation)
      @list.any? {|inv, value| inv == invocation}
    end

    def empty?
      @list.empty?
    end

  end

  class InvocationList < Array
    def include?(method, *args)
      if method.is_a? Symbol
        self.any? do |i|
          i.method == method
        end
      else
        raise "Haven't implemented include? for anything but Symbols (given #{method.class})"
      end
    end
    alias_method :has_received?, :include?

    def [](index)
      case index
      when Fixnum
        self.at(index)
      when Symbol
        InvocationList.new self.select{|i| i.method == index }
      else
        raise "Unknown index type: #{index.class}"
      end
    end

    def count
      length
    end

  end

end

def should_be_a_dingus(object)
  lambda {
    object._dingus?
  }.should_not raise_error(NoMethodError)
end

def should_not_be_a_dingus(object)
  lambda {
    object._dingus?
  }.should raise_error(NoMethodError)
end

describe RDingus::DefinitionProxy do
  before :each do
    @rdingus = RDingus.new
    @def = RDingus::DefinitionProxy.new(@rdingus)
  end

  describe "when given a sub defining block" do
    before :each do
      @def._define do
        b_method :result
      end
      @invocation = RDingus::InvocationRecord.new(@rdingus, :b_method)
    end

    it "should record the method's result" do
      should_not_be_a_dingus @def._list[@invocation]
      @def._list[@invocation].should == :result
    end
  end

  describe "when calling methods to record" do
    before :each do
      @def.a_method(:arguments) { :return_value }
      @invocation = RDingus::InvocationRecord.new(@rdingus, :a_method)
    end

    it "should record them in an InvocationResultHash" do
      @def._list.should be_kind_of(RDingus::InvocationResultHash)
    end

    it "should use the given InvocationResultHash if present" do
      @hash = RDingus::InvocationResultHash.new
      @def = RDingus::DefinitionProxy.new @rdingus, @hash
      @def.a_method { :test }
      @def._list[@invocation].should_not be_nil
    end

    describe "with a block" do
      it "should store the block" do
        @def.a_method { :block }
        should_not_be_a_dingus @def._list[@invocation]
        @def._list[@invocation].should be_instance_of(Proc)
      end
    end

    describe "with just a return value" do
      it "should store the value" do
        @def.a_method :value
        should_not_be_a_dingus @def._list[@invocation]
        @def._list[@invocation].should == :value
      end
    end

    describe "with no value or block" do
      it "should return a new dingus' definition proxy" do
        should_not_be_a_dingus @def.a_method._list
        @def.a_method._list.should be_empty
      end
    end

  end

end

describe RDingus do
  before :each do
    @rdingus = RDingus.new
  end

  it "should be recognized by the custom matcher 'be_a_dingus'" do
    should_be_a_dingus(@rdingus)
  end

  it "should return an RDingus on method calls" do
    should_be_a_dingus(@rdingus.a_method)
  end

  it "should return the same RDingus for the same method invocation" do
    @rdingus.a_method.__id__.should == @rdingus.a_method.__id__
  end

  it "should return a different RDingus for a different method invocation" do
    @rdingus.a_method.__id__.should_not == @rdingus.b_method.__id__
  end

  it "should return a different RDingus for the same method invocation but with different arguments" do
    @rdingus.a_method.__id__.should_not == @rdingus.a_method(:argument).__id__
  end

  it "should return self on dup" do
    @rdingus.dup.__id__.should == @rdingus.__id__
  end

  it "should return self on clone" do
    @rdingus.clone.__id__.should == @rdingus.__id__
  end

  describe "when calling .inspect" do
    it "should not return an RDingus" do
      should_not_be_a_dingus @rdingus.inspect
    end

    it "should return a string" do
      # This has to be done in reverse because "should" is not
      # defined on a dingus
      String.should === @rdingus.inspect
    end
  end

  describe "when defining return values" do
    # Comparisons with a dingus can be tricky. They will always be "true"
    # (or technically "non nil/false") if compared with something else.
    # You have to check to make sure it's *not* a dingus before making
    # a comparison.

    it "should return what's assigned" do
      @rdingus._define.a_method { :shell }
      should_not_be_a_dingus @rdingus.a_method
      :shell.should == @rdingus.a_method
    end

    it "should return false if assigned" do
      @rdingus._define.a_method { false }
      should_not_be_a_dingus @rdingus.a_method
      false.should == @rdingus.a_method
    end

    it "should return nil if assigned" do
      @rdingus._define.a_method { nil }
      should_not_be_a_dingus @rdingus.a_method
      nil.should == @rdingus.a_method
    end

    it "should not remember as a method call" do
      @rdingus._define.a_method { "something" }
      @rdingus._calls.should be_empty
    end

    it "should not forget other method calls" do
      @rdingus.remember_me
      @rdingus._define.a_method "something"
      @rdingus._calls.map{|i|i.method}.should == [:remember_me]
    end

    describe "and within the result proc" do

      it "should provide access to method name" do
        @rdingus._define.a_method { raise method.to_s }
        lambda { @rdingus.a_method }.should raise_error("a_method")
      end

      it "should provide access to called arguments" do
        @rdingus._define.a_method("arguments") { raise args.first }
        lambda { @rdingus.a_method("arguments") }.should raise_error("arguments")
      end

      it "should provide access to passed block" do
        @rdingus._define.a_method { raise block.call }
        lambda {
          @rdingus.a_method do
            "raise me"
          end
        }.should raise_error("raise me")
      end

    end

    describe "of nested method calls" do
      it "should return what's assigned" do
        @rdingus._define.a_method.b_method :stump
        should_not_be_a_dingus @rdingus.a_method.b_method
        :stump.should == @rdingus.a_method.b_method
      end

      it "should not remember as a method call" do
        @rdingus._define.a_method.b_method "something"
        @rdingus._calls.should be_empty
      end
    end

    describe "with arbitrary arguments" do
      before :each do
        @rdingus._define.a_method(:any) { :stump }
      end

      it "should return what's assigned given any arguments" do
        Symbol.should === @rdingus.a_method(:argument)
        :stump.should == @rdingus.a_method(:argument)
      end

      it "should return what's assigned with no arguments" do
        Symbol.should === @rdingus.a_method
        :stump.should == @rdingus.a_method
      end
    end

    describe "with specific arguments" do
      before :each do
        @rdingus._define.a_method(:argument) { :stump }
      end

      it "should return what's assigned" do
        Symbol.should === @rdingus.a_method(:argument)
        :stump.should == @rdingus.a_method(:argument)
      end

      it "should return an RDingus if arguments don't match" do
        should_be_a_dingus @rdingus.a_method(:argument, :argument2)
      end
    end

    describe "with block syntax" do
      before :each do
        @rdingus._define do
          a_method { :stump }
        end
      end

      it "should return what's assigned" do
        should_not_be_a_dingus @rdingus.a_method
        @rdingus.a_method.should == :stump
      end

      describe "within a block syntax" do
        it "should return what's assigned" do
          @rdingus._define do
            a_method._define do
              b_method :stump
            end
          end
          should_not_be_a_dingus @rdingus.a_method.b_method
          @rdingus.a_method.b_method.should == :stump
        end
      end
    end
  end

  describe "when specifying exceptions" do
    it "should raise given exception" do
      @rdingus._define.raise_me { raise "Exception" }
      lambda { @rdingus.raise_me }.should raise_error("Exception")
    end

    it "should not remember as a method call" do
      @rdingus._define.raise_me {raise "Exception" }
      lambda { @rdingus.raise_me }.should raise_error("Exception")
      @rdingus._calls.map{|i|i.method}.should == [:raise_me]
    end

    it "should not forget other method calls" do
      @rdingus.remember_me
      @rdingus._define.raise_me { raise "Exception" }
      lambda { @rdingus.raise_me }.should raise_error("Exception")
      @rdingus._calls.map{|i|i.method}.should == [:remember_me, :raise_me]
    end
  end

  describe "recording invocations" do
    it "should remember methods invoked" do
      @rdingus.sandwich
      :sandwich.should == @rdingus._calls.first.method
    end

    it "should remember with arguments invoked" do
      @rdingus.sandwich(:with_cheese)
      :with_cheese.should == @rdingus._calls.first.args.first
    end

    it "should count method invocations" do
      @rdingus.sandwich
      @rdingus._calls.count.should == 1
    end

  end

end


describe RDingus::InvocationRecord do
  before :each do
    @rdingus = RDingus.new
    @invocation_record = RDingus::InvocationRecord.new(@rdingus, :method, [:arg1, :arg2])
  end

  it "should provide access to it's owning RDingus" do
    @invocation_record.dingus.should == @rdingus
  end

  it "should be equal for same method and arguments" do
    RDingus::InvocationRecord.new(@rdingus, :method, [:arg1, :arg2]).should == @invocation_record
  end

  it "should not be equal for different method" do
    RDingus::InvocationRecord.new(@rdingus, :method2, [:arg1, :arg2]).should_not == @invocation_record
  end

  it "should not be equal for different arguments" do
    RDingus::InvocationRecord.new(@rdingus, :method, [:arg2, :arg3]).should_not == @invocation_record
  end

  it "should define == the same as eql?" do
    RDingus::InvocationRecord.new(@rdingus, :method, [:arg1, :arg2]).should be_eql(@invocation_record)
  end

  describe "when told to accept any arguments" do
    before :each do
      @invocation_record = RDingus::InvocationRecord.new(@rdingus, :method, [:any])
    end

    it "should be equal for same method and same arguments" do
      RDingus::InvocationRecord.new(@rdingus, :method, [:any]).should == @invocation_record
    end

    it "should be equal for same method and different arguments" do
      RDingus::InvocationRecord.new(@rdingus, :method, [:other, :args]).should == @invocation_record
    end

    it "should not be equal for different method" do
      RDingus::InvocationRecord.new(@rdingus, :method2, [:arg1, :arg2]).should_not == @invocation_record
    end
  end

  it "should convert to a useful string" do
    @invocation_record.to_s.should == "method(:arg1, :arg2)"
  end

  it "should have a useful inspect result" do
    @invocation_record.value = :arg3
    @invocation_record.inspect.should == "#<Invocation \"method(:arg1, :arg2)\" => :arg3>"
  end
end

describe RDingus::InvocationResultHash do
  before :each do
    @rdingus = RDingus.new
    @invocation = RDingus::InvocationRecord.new(@rdingus, :method, [:arg1, :arg2])
    @invocation_list = RDingus::InvocationResultHash.new
  end

  it "should store and retrieve for same invocation" do
    @invocation_list[@invocation] = "test"
    @invocation_list[@invocation].should == "test"
  end

  it "should store and retrieve for equivalent invocations" do
    @invocation_list[RDingus::InvocationRecord.new(@rdingus, :method, [:any])] = 'test'
    @invocation_list[@invocation].should == "test"
  end

  it "should not store and retrieve for non equivalent invocations" do
    @invocation_list[RDingus::InvocationRecord.new(@rdingus, :method2)] = "test"
    @invocation_list[@invocation].should_not == "test"
  end

  it "should know if a value is defined" do
    @invocation_list[@invocation] = "test"
    @invocation_list.defined?(@invocation).should be_true
  end

  it "should know it has a value even if value is nil" do
    @invocation_list[@invocation] = false
    @invocation_list[@invocation].should == false
    @invocation_list.defined?(@invocation).should be_true
  end

  it "should know it has a value even if value is false" do
    @invocation_list[@invocation] = nil
    @invocation_list[@invocation].should == nil
    @invocation_list.defined?(@invocation).should be_true
  end

  describe "when redefining invocation" do
    it "should use the last one" do
      @invocation_list[@invocation] = "first"
      @invocation_list[RDingus::InvocationRecord.new(@rdingus, :method, [:any])] = "second"
      @invocation_list[@invocation].should == "second"
    end
  end

end

describe RDingus::InvocationList do
  before :each do
    @rdingus = RDingus.new
    @list = RDingus::InvocationList.new
  end

  describe "when adding method invocations" do
    it "should allow append" do
      @list << :test
      @list.to_a.should == [:test]
    end
  end

  describe "when counting method invocations" do
    before :each do
      @list << RDingus::InvocationRecord.new(@rdingus, :some_method)
      @list << RDingus::InvocationRecord.new(@rdingus, :some_method_2)
    end

    describe "without sub calls" do
      it "should be equal to length" do
        @list.count.should == @list.length
      end
    end

  end

  describe "when querying using include?" do

    describe "with just a method name symbol" do
      before :each do
        @invocation = RDingus::InvocationRecord.new(@rdingus, :some_method)
      end

      describe "that is in the list" do
        before :each do
          @list << @invocation
        end

        it "should find the invocation" do
          @list.should include(:some_method)
        end
      end

      describe "that is not in the list" do
        it "should not find the invocation" do
          @list.should_not include(:some_method)
        end
      end
    end

    it "should alias has_received? to include?" do
      @list << RDingus::InvocationRecord.new(@rdingus, :some_method)
      @list.should have_received(:some_method)
    end

  end

  describe "when indexing via []" do
    before :each do
      @invocation1 = RDingus::InvocationRecord.new(@rdingus, :some_method)
      @invocation2 = RDingus::InvocationRecord.new(@rdingus, :method_2, [:arg1, :arg2])
      @invocation3 = RDingus::InvocationRecord.new(@rdingus, :method_3)
      @list << @invocation1; @list << @invocation2; @list << @invocation3
    end

    describe "with integers" do
      it "should return the requested invocation in the sequence" do
        @list[2].method.should == :method_3
      end
    end

    describe "with a method name symbol" do
      before :each do
        @list << @invocation2
      end

      it "should return a new list" do
        @list[:method_2].should be_kind_of(RDingus::InvocationList)
      end

      it "should have proper number of elements" do
        @list[:method_2].length.should == 2
      end

      it "should only have invocations of the given method" do
        @list[:method_2].each {|i| i.method.should == :method_2 }
      end
    end

  end

end



class Person
  attr_accessor :name
  attr_accessor :shoe_size

  def eat(sandwich)
    @sandwich = sandwich
    @sandwich.cut :in => 2
    @sandwich.take_a_bite
  end

  def drop(sandwich)
    sandwich.drop
  end

  def opinion_of_sandwich
    if @sandwich.cheese.spicy?
      "yummy!"
    else
      "bland"
    end
  end

end

describe Person do
  before :each do
    @person = Person.new
  end

  describe "when specifying a shoe size" do

    it "should save the shoe size" do
      @person.shoe_size = 4
      @person.shoe_size.should == 4
    end

  end

  describe "when using a sandwich" do
    before :each do
      @sandwich = RDingus.new
      @person.eat(@sandwich)
    end

    it "should be able to cut a sandwhich" do
      @sandwich._calls.first.method.should == :cut
    end

    it "should cut into two slices" do
      @sandwich._calls[0].args[0].should == {:in => 2}
    end

    it "should take a bite" do
      @sandwich._calls.should have_received(:take_a_bite)
    end

    it "should not have been dropped" do
      @sandwich._calls.should_not have_received(:dropped)
    end

    it "should raise an exception if it drops the sandwich" do
      @sandwich._define.drop { raise "Dropped Sandwich!" }
      lambda { @person.drop(@sandwich) }.should raise_error("Dropped Sandwich!")
    end

    describe "that has spicy cheese" do
      before :each do
        @sandwich._define.cheese.spicy? true
      end

      it "should have an opinion of 'yummy!'" do
        @person.opinion_of_sandwich.should == "yummy!"
      end
    end

    describe "that does not have spicy cheese (block syntax)" do
      before :each do
        @sandwich._define do
          cheese.spicy? false
        end
      end

      it "should have an opinion of 'bland'" do
        @person.opinion_of_sandwich.should == "bland"
      end
    end

    describe "that does not have spicy cheese" do
      before :each do
        @sandwich._define.cheese.spicy? false
      end

      it "should have an opinion of 'bland'" do
        @person.opinion_of_sandwich.should == "bland"
      end
    end
  end

end