PropSchema

An extension of both Ecto.Schema and ExUnitProperties for auto-generation of changeset property tests. Consists of two main modules: PropSchema and PropSchema.TestHarness

Usage

Look at the documentation for full usage

https://hexdocs.com/prop_schema

Basic Example

In example_module.ex:

defmodule ExampleModule do
  use PropSchema
  alias Ecto.Changeset

  prop_schema "example" do
    prop_field(:example_string, :string, string_type: :alphanumeric, required: true)
    prop_field(:example_int, :integer, positive: true, required: false)
    field(:example_float, :float)
  end

  def changeset(schema, data) do
    schema
    |> Changeset.cast(data, [:example_string, :example_int, :example_float])
    |> Changeset.validate_required([:example_string])
  end
end

In example_module_test.ex:

defmodule ExampleModuleTest do
  use PropSchema.TestHarness, to_test: PropSchema.ExampleModule
end

Then run mix test. In this example it will make 3 prop tests.

Or for a more realistic example see example module, properties, and generated tests.

Tips for First Time Users

I would suggest following this 6 step process your first time through (to get a feel for how this library builds on Ecto.Schema and StreamData to generate dummy data and tests)

1. Start with simply creating your Ecto.Schema and define your changeset requirements as you would normally do.
2. Modify that schema by replacing all the macros with the corresponding PropSchema macros (Don't worry about adding any options at this point)
3. Create a .iex.mix file where you define a module that
   1. Uses PropSchema.Stream.generate_complete_map/2 with your new schema's module as its first argument and
   2. Defines a public function that runs complete() |> Enum.at(0) (This will generate a random map that you can run through your changeset)
4. Determine what is unsatisfactory with the resulting map and add generate_prop/3 functions to a new "AdditionalProperties" module for each key of that map you'd like to generate (see PropSchema.AdditionalProperties for directions, or examine this: example)
5. Place this new module as the second argument of the PropSchema.Stream.generate_complete_map/2 call in your .iex.exs file.
6. Once the generated map is satisfactory, use the PropSchema.TestHarness module to generate your tests with ease.