Question

I have a table (Dishes) that has a column (nutrition_facts) that stores key/value data (similar to hstore in a PostgreSQL database).

I’ve defined a new instance of a Dish in my fixtures folder as such:

nutrition_facts:
  id: 6
  name: Dish 6
  category: Cat 1
  description: Something about Dish 6
  price: 15.32
  menu_id: 1
  nutrition_facts:
    serving_size:
    calories: 392

But I can’t seem to make the following assertions work when I run rake test:units — it fails on the first assert_not_nil

  test "no serving size with calories" do
    dish = dishes(:nutrition_facts)

    assert_not_nil(dish.calories)
    assert_nil(dish.serving_size)
    assert !dish.save, "Saved dish when serving size wasn't defined while calories was"
  end

How can I test for the individual calories and serving_size values without testing the entire nutrition_facts field?

In short, I’m trying to test the following validation (from my dish.rb file), which works when I run the application in a browser:

  # Check 'serving size' isn't blank only if 'calories' is defined
  validates_presence_of :serving_size, :if => Proc.new { |val| !val.calories.blank? }

Answer 1

I was able to get it to work by doing defining my nutrition_facts column’s key/value as such:

nutrition_facts: <%= {:serving_size => nil, :calories => 33}.to_yaml.inspect %>

So in my fixtures, it’ll look like this:

nutrition_facts:
  id: 6
  name: Dish 6
  category: Cat 1
  description: Something about Dish 6
  price: 15.32
  menu_id: 1
  nutrition_facts: <%= {:serving_size => nil, :calories => 33}.to_yaml.inspect %>

With my unit test now looking like this:

  test "no serving size with calories" do
    dish = dishes(:nutrition_facts)

    assert_not_nil(dish.calories)
    assert_nil(dish.serving_size)
    assert !dish.save, "Saved dish when serving size wasn't defined while calories was"
  end

Source: Fixtures and serialized attributes in Ruby on Rails