Wallaby

Wallaby helps you test your web applications by simulating user interactions. By default it runs each TestCase concurrently and manages browsers for you.

Official Documentation

Features

Intuitive DSL for interacting with pages.
Manages multiple browser processes.
Works with Ecto's test Sandbox.

Setup

Add wallaby to your list of dependencies in mix.exs:

def deps do
  [{:wallaby, "~> 0.16.1"}]
end

Then ensure that Wallaby is started in your test_helper.exs:

{:ok, _} = Application.ensure_all_started(:wallaby)

Phoenix

If you're testing a Phoenix application with Ecto then you can enable concurrent testing by adding the Phoenix.Ecto.SQL.Sandbox to your Endpoint.

Note: This requires Ecto v2.0.0-rc.0 or newer.

Note 2: It's important that this is at the top of endpoint.ex, before any other plugs.

# lib/endpoint.ex

if Application.get_env(:your_app, :sql_sandbox) do
  plug Phoenix.Ecto.SQL.Sandbox
end

# config/test.exs

# Make sure Phoenix is setup to serve endpoints
config :your_app, YourApplication.Endpoint,
  server: true

config :your_app, :sql_sandbox, true

Then in your test_helper.exs you can provide some configuration to Wallaby.

# test/test_helper.exs

Application.put_env(:wallaby, :base_url, YourApplication.Endpoint.url)

PhantomJS

Wallaby requires PhantomJS. You can install PhantomJS through NPM or your package manager of choice:

$ npm install -g phantomjs

Wallaby will use whatever phantomjs you have installed in your path. If you need to specify a specific phantomjs you can pass the path in the configuration:

config :wallaby, phantomjs: "some/path/to/phantomjs"

You can also pass arguments to PhantomJS through the phantomjs_args config setting, e.g.:

config :wallaby, phantomjs_args: "--webdriver-logfile=phantomjs.log"

Writing tests

Its easiest to add Wallaby to your test suite by creating a new Case Template:

defmodule YourApp.AcceptanceCase do
  use ExUnit.CaseTemplate

  using do
    quote do
      use Wallaby.DSL

      alias YourApp.Repo
      import Ecto
      import Ecto.Changeset
      import Ecto.Query

      import YourApp.Router.Helpers
    end
  end

  setup tags do
    :ok = Ecto.Adapters.SQL.Sandbox.checkout(YourApp.Repo)

    unless tags[:async] do
      Ecto.Adapters.SQL.Sandbox.mode(YourApp.Repo, {:shared, self()})
    end

    metadata = Phoenix.Ecto.SQL.Sandbox.metadata_for(YourApp.Repo, self())
    {:ok, session} = Wallaby.start_session(metadata: metadata)
    {:ok, session: session}
  end
end

Then you can write tests like so:

defmodule YourApp.UserListTest do
  use YourApp.AcceptanceCase, async: true

  test "users have names", %{session: session} do
    first_employee =
      session
      |> visit("/users")
      |> find(Query.css(".dashboard"))
      |> all(Query.css(".user"))
      |> List.first
      |> find(Query.css(".user-name"))
      |> text

    assert first_employee == "Chris"
  end
end

DSL

The full documentation for the DSL is in the official documentation.

Navigation

You can navigate directly to pages with visit:

visit(session, "/page.html")
visit(session, user_path(Endpoint, :index, 17))

Its also possible to click links directly:

click(session, Query.link("Page 1"))

Querying & Finding

Queries are used to find and interact with elements through a browser (see Wallaby.Browser). You can create queries like so:

Query.css(".some-css")
Query.xpath(".//input")
Query.button("Some Button")

These queries can then be used to find or interact with an element

@user_form   Query.css(".user-form")
@name_field  Query.text_field("Name")
@email_field Query.text_field("Email")
@save_button Query.button("Save")

find(page, @user_form, fn(form) ->
  form
  |> fill_in(@name_field, with: "Chris")
  |> fill_in(@email_field, with: "c@keathley.io")
  |> click(@save_button)
end)

If a callback is passed to find then the find will return the parent and the callback can be used to interact with the element.

By default Wallaby will block until it can find the matching element. This is used to keep asynchronous tests in sync (as discussed below).

Nodes can be found by their inner text.

# <div class="user">
#   <span class="name">
#     Chris K
#   </span>
# </div>

find(page, Query.css(".user", text: "Chris K"))

Interacting with forms

There are a few ways to interact with form elements on a page:

fill_in(session, Query.text_field("First Name"), with: "Chris")
clear(session, Query.text_field("last_name"))
click(session, Query.option("Some option"))
click(session, Query.button("Some Button"))

Windows and Screenshots

Its possible to interact with the window and take screenshots:

resize_windowe(session, 100, 100)
window_size(session)
take_screenshot(session)

All screenshots are saved to a screenshots directory in the directory that the tests were run in.

If you want to customize the screenshot directory you can pass it as a config value:

# config/test.exs
config :wallaby, screenshot_dir: "/file/path"

# test_helper.exs
Application.put_env(:wallaby, :screenshot_dir, "/file/path")

Automatic screenshots

You can automatically take screenshots on an error:

# config/test.exs
config :wallaby, screenshot_on_failure: true

# test_helper.exs
Application.put_env(:wallaby, :screenshot_on_failure, true)

Javascript

Asynchronous code.

It can be difficult to test asynchronous javascript code. You may try to interact with an element that isn't visible on the page. Wallaby's finders try to help mitigate this problem by blocking until the element becomes visible. You can use this strategy by writing tests in this way:

session
|> click(Query.button("Some Async Button"))
|> find(Query.css(".async-result"))

Javascript logging and errors

Wallaby captures both javascript logs and errors. Any uncaught exceptions in javascript will be re-thrown in elixir. This can be disabled by specifying js_errors: false in your Wallaby config.

Javascript logs are written to :stdio by default. This can be changed to any IO device by setting the :js_logger option in your wallaby config. For instance if you want to write all Javascript console logs to a file you could do something like this:

{:ok, file} = File.open("browser_logs.log", [:write])
Application.put_env(:wallaby, :js_logger, file)

Logging can be disabled by setting :js_logger to nil.

Contributing

Wallaby is a community project. PRs and Issues are greatly welcome.

drapergeek/wallaby