Skip to content

testing.md

Latest commit

 

History

History
133 lines (95 loc) · 2.95 KB

testing.md

File metadata and controls

133 lines (95 loc) · 2.95 KB

Testing

Setup

# test/test_helper.exs
Application.put_env(:courgette, :animations_enabled, false)
ExUnit.start()

In each test module:

defmodule MyAppTest do
  use ExUnit.Case
  use Courgette.ComponentTestHelpers

  # ...
end

Test Helpers

mount/1,2

Start a component in a headless environment (no real terminal).

view = mount(MyApp)
view = mount(MyApp, width: 120, height: 40, initial_assigns: %{items: []})

Options:

  • :width — buffer width (default 80)
  • :height — buffer height (default 24)
  • :initial_assigns — map passed to mount/1 (default %{})

Returns a view handle used by all other helpers.

send_event/2

Send a parsed event directly to the component. Synchronous — returns after the event is fully processed.

send_event(view, {:key, {:char, "a"}})
send_event(view, {:key, :enter})
send_event(view, {:key, {:ctrl, "c"}})

send_tab/1 / send_shift_tab/1

Convenience for focus cycling:

send_tab(view)        # sends {:key, :tab}
send_shift_tab(view)  # sends {:key, {:shift, :tab}}

send_info/2

Send a raw Erlang message to the component's handle_info/2. Synchronous.

send_info(view, {:name_changed, "Alice"})

render_text/1

Extract all visible text from the last rendered tree. Walks depth-first, joins with spaces.

assert render_text(view) =~ "Hello"
assert render_text(view) =~ "Count: 5"

render_tree/1

Get the raw Element.t() tree for structural assertions.

tree = render_tree(view)
assert tree.type == :box
assert length(tree.children) == 3

Complete Test Example

defmodule CounterTest do
  use ExUnit.Case
  use Courgette.ComponentTestHelpers

  defmodule Counter do
    use Courgette.App

    def mount(_assigns), do: {:ok, %{count: 0}}

    def render(assigns) do
      text(do: "Count: #{assigns.count}")
    end

    def handle_event({:key, :arrow_up}, assigns) do
      {:noreply, update(assigns, :count, &(&1 + 1))}
    end

    def handle_event(_event, assigns), do: {:noreply, assigns}
  end

  test "renders initial state" do
    view = mount(Counter)
    assert render_text(view) =~ "Count: 0"
  end

  test "increments on arrow up" do
    view = mount(Counter)
    send_event(view, {:key, :arrow_up})
    assert render_text(view) =~ "Count: 1"
  end

  test "ignores unknown keys" do
    view = mount(Counter)
    send_event(view, {:key, {:char, "x"}})
    assert render_text(view) =~ "Count: 0"
  end
end

Key Notes

  • All helpers are synchronous. After send_event or send_info returns, the component has finished processing and re-rendering.
  • render_text/1 joins depth-first. It collects all string children from the element tree, so nested text elements are flattened.
  • No real terminal is involved. Tests use a headless renderer — no raw mode, no ANSI output.
  • Animations should be disabled in test_helper.exs to avoid timers and flaky tests.