Running doctests via Mix

[Dave Thomas]

I've been playing with getting doctests to run without having to write a separate test module. I'm working towards having a mix task that takes a list of .ex files and just runs the doctests in them.

As a first spike, I'm trying it with a static module inside the task itself

https://gist.github.com/pragdave/5393324

However, when I run it, I get the failures below. Is there an ast_to_string or equivalent to I can see what's wrong with the module I'm generating? Alternatively, can anyone give me a hint where to start digging?

Cheers

Dave

Failures:

  1) test moduledoc at Mix.Tasks.Doctest.Wombat (1) (Mix.Tasks.Doctest.InternalTests)

     ** (FunctionClauseError) no function clause matching: Mix.Tasks.Doctest.InternalTests."test moduledoc at Mix.Tasks.Doctest.Wombat (1)"([test: ExUnit.Test[name: :"test moduledoc at Mix.Tasks.Doctest.Wombat (1)", case: Mix.Tasks.Doctest.InternalTests, failure: nil], case: Mix.Tasks.Doctest.InternalTests])

     at nofile:1

  2) test moduledoc at Mix.Tasks.Doctest.Wombat (2) (Mix.Tasks.Doctest.InternalTests)

     ** (FunctionClauseError) no function clause matching: Mix.Tasks.Doctest.InternalTests."test moduledoc at Mix.Tasks.Doctest.Wombat (2)"([test: ExUnit.Test[name: :"test moduledoc at Mix.Tasks.Doctest.Wombat (2)", case: Mix.Tasks.Doctest.InternalTests, failure: nil], case: Mix.Tasks.Doctest.InternalTests])

     at nofile:1

Finished in 0.00 seconds

[José Valim]

Dave,

Macro.to_binary is going to convert an ast to binary.

I would also suggest using the quote mechanism to generate the code you desire.

Here is an example. Assuming you have a list of tuples with the function names and their implementation, similar to the ones you get from doctest:

    list = quote do: [foo: 1 + 2, bar: 3 + 5]

    defs = Enum.map list, fn { name, impl } ->

      quote do

        def unquote(name)(_), do: unquote(impl)

      end

    end

    contents = quote do

      use ExUnit.Case, async: true

      # Splice the functions in the module body.

      # unquote would work just fine too

      unquote_splicing(defs)

    end

    Module.create(MyModule, contents, __ENV__.location)

    MyModule.foo(:whatever) #=> 3

          

You could also use Code.eval_quoted as you were, but in general Elixir provides tools so you can avoid any of the evaling functions.

José Valim

www.plataformatec.com.br

Skype: jv.ptec

Founder and Lead Developer

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[Dave Thomas]

I would also suggest using the quote mechanism to generate the code you desire.

And that indeed worked (and is infinitely more elegant than building the ast by hand :)

I'll finish this up tomorrow. Would you consider a pull request for it?

Dave

[José Valim]

I'll finish this up tomorrow. Would you consider a pull request for it?

I thought about it originally and I am undecided. While it seems interesting, I couldn't find a scenario where I would use it directly, since setting up the test framework is easy. If there are good use cases for it though, I don't see why not. :)

Also, I just realized you could call doctest directly from the test case. So you probably just need this:

    contents = quote do

      use ExUnit.Case, async: true

      Enum.each modules_to_test, doctest(&1)

    end

    Module.create(MyModule, contents, __ENV__.location)

It takes all the fun away though!