Class: Minitest::Proptest::Gen

Inherits:
Object
  • Object
show all
Defined in:
lib/minitest/proptest/gen.rb,
lib/minitest/proptest/gen/value_generator.rb

Overview

Generic value generation and shrinking implementations, and support for built-in types.

Defined Under Namespace

Classes: ASCIIChar, Bool, Char, Float32, Float64, Int16, Int32, Int64, Int8, UInt16, UInt32, UInt64, UInt8, ValueGenerator

Constant Summary collapse

MAX_SIZE =

Default maximum random value size is the local architecture’s word size

((1 << (1.size * 8)) - 1)
SIGN_BIT = 
(1 << ((1.size * 8) - 1))

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(random) ⇒ Gen

Returns a new instance of Gen.



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# File 'lib/minitest/proptest/gen.rb', line 60

def initialize(random)
  @random    = random
  @generated = []
end

Instance Attribute Details

#generated ⇒ Object (readonly)

Returns the value of attribute generated.



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# File 'lib/minitest/proptest/gen.rb', line 28

def generated
  @generated
end

Class Method Details

.create_type_constructor(arity, classes) ⇒ Object 



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# File 'lib/minitest/proptest/gen.rb', line 32

def self.create_type_constructor(arity, classes)
  constructor = ->(_c1) do
    if classes.length == arity
      f.call(*classes)
    else
      ->(c2) { constructor.call(c2) }
    end
  end
end

.generator_for(klass, &f) ⇒ Object 



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# File 'lib/minitest/proptest/gen.rb', line 42

def self.generator_for(klass, &f)
  new_class = Class.new(ValueGenerator)
  new_class.define_method(:initialize) do |g|
    @entropy         = ->(b = MAX_SIZE) { (@generated << g.rand(b)).last }
    @generated       = []
    @generator       = self.method(:generator).curry
    @parent_gen      = g
    @value           = nil
    @type_parameters = []
  end

  new_class.define_method(:generator, &f)

  instance_variable_get(:@_generators)[klass] = new_class
  self.const_set("#{klass.name}Gen".split('::').last, new_class)
  new_class
end

Instance Method Details

#for(*classes) ⇒ Object 



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# File 'lib/minitest/proptest/gen.rb', line 69

def for(*classes)
  generators = self.class.instance_variable_get(:@_generators)
  case classes.length
  when 0
    raise(TypeError, "A generator for #{classes.join(' ')} is not known.  Try adding it with Gen.generator_for.")
  when 1
    gen = generators[classes.first]
    if gen.bound_max > 1
      c = rand(gen.bound_max - gen.bound_min + 1) + gen.bound_min
      c.times.reduce(gen.empty(self)) { |g, _| g.append(gen.new(self)) }
    else
      gen.new(self)
    end
  else
    classgen = ->() do
      classes[1..].map do |k|
        if k.is_a?(Array)
          self.for(*k)
        else
          self.for(k)
        end
      end
    end
    cs = classgen.call

    gen = generators[classes.first]
    typegen = gen.bound_min < 1 ? gen.empty(self) : gen.new(self)
    typegen.type_parameters = cs
    typegen.prefix_entropy_generation(cs)

    if gen.bound_max > 1
      c = rand(gen.bound_max - gen.bound_min + 1) + gen.bound_min
      c.times.reduce(typegen) do |g, _|
        cs2 = classgen.call
        g2 = gen.new(self)
        g2.type_parameters = cs2
        g2.prefix_entropy_generation(cs2)
        g.append(g2)
      end
    else
      typegen
    end
  end
end

#rand(max_size = MAX_SIZE) ⇒ Object 



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# File 'lib/minitest/proptest/gen.rb', line 65

def rand(max_size = MAX_SIZE)
  (@generated << @random.rand(max_size)).last
end