gistfile1.rb

require 'mrproper'

# assuming Croupier.normal(i, m = 0, v = 1) returns an array of i elements following a normal distribution with mean m and variance v

properties 'normal(i, m, v)' do
  data :i => 1..9999,
       :m => -10.0..10.0,
       :v => 0.0..10.0
  
  property 'has i elements' do |data|
    assert_equal data[:i], Croupier.normal(data[:i], data[:m], data[:v]).size
  end
  
  property 'is distributed like a normal distribution' do |data|
    assert_normal Croupier.normal(data[:i], data[:m], data[:v])
  end
  
  property 'has mean m' do |data|
    assert_equal data[:m], mean(Croupier.normal(data[:i], data[:m], data[:v]))
    # actually you shouldn't test they're equal but “close”
  end
  
  property 'has variance v' do |data|
    assert_equal data[:v], variance(Croupier.normal(data[:i], data[:m], data[:v]))
    # actually you shouldn't test they're equal but “close”
  end
end

properties 'normal(i)' do
  data 1..9999
  
  property 'has mean 0' do |data|
    assert_equal 0.0, mean(Croupier.normal(data[:i], data[:m], data[:v]))
    # actually you shouldn't test they're equal but “close”
  end
  
  property 'has variance 1' do |data|
    assert_equal 1.0, variance(Croupier.normal(data[:i], data[:m], data[:v]))
    # actually you shouldn't test they're equal but “close”
  end
end

def assert_normal(sample)
  # come on guys, you're supposed to know math!
end

def mean(sample)
  # come on guys, you're supposed to know math!
end

def variance(sample)
  # come on guys, you're supposed to know math!
end