Allow setting the preferred JS package runner (npx, bunx) (#51)

* Support configuring the package runner and the assets directory
* Deprecate `cli` option

Author: Wigny

config/test.exs

@@ -14,7 +14,7 @@ config :phoenix_test,
   endpoint: PhoenixTest.Endpoint,
   otp_app: :phoenix_test_playwright,
   playwright: [
-    cli: "priv/static/assets/node_modules/playwright/cli.js",
+    assets_dir: "priv/static/assets",
     headless: System.get_env("PW_HEADLESS", "true") in ~w(t true),
     screenshot: System.get_env("PW_SCREENSHOT", "false") in ~w(t true),
     trace: System.get_env("PW_TRACE", "false") in ~w(t true),

lib/phoenix_test/playwright/case.ex

@@ -101,8 +101,11 @@ defmodule PhoenixTest.Playwright.Case do
       Playwright.BrowserContext.stop_tracing(browser_context_id, path)
 
       if config[:trace] == :open do
-        cli_path = Path.join(File.cwd!(), Playwright.Port.cli_path())
-        System.cmd(cli_path, ["show-trace", path])
+        System.cmd(
+          Playwright.Config.global(:runner),
+          ["playwright", "show-trace", path],
+          cd: Playwright.Config.global(:assets_dir)
+        )
       end
     end)
   end

lib/phoenix_test/playwright/config.ex

@@ -12,9 +12,22 @@ schema =
       type: {:in, browsers},
       type_doc: "`#{Enum.map_join(browsers, " | ", &":#{&1}")}`"
     ],
+    runner: [
+      default: "npx",
+      type_spec: quote(do: binary()),
+      type_doc: "`t:binary/0`",
+      type: {:custom, PhoenixTest.Playwright.Config, :__validate_runner__, []},
+      doc:
+        "The JS package runner to use to run the Playwright CLI. Accepts either a binary executable exposed in PATH or the absolute path to it."
+    ],
+    assets_dir: [
+      default: "./assets",
+      type: :string,
+      doc: "The directory where the JS assets are located and the Playwright CLI is installed."
+    ],
     cli: [
-      default: "assets/node_modules/playwright/cli.js",
-      type: :string
+      type: {:custom, PhoenixTest.Playwright.Config, :__validate_cli__, []},
+      deprecated: "Use `assets_dir` instead."
     ],
     executable_path: [
       type: :string,
@@ -65,7 +78,7 @@ schema =
     accept_dialogs: [
       default: true,
       type: :boolean,
-      doc: "Accept browser dialogs (`alert()`, `confirm()`, `prompt()`"
+      doc: "Accept browser dialogs (`alert()`, `confirm()`, `prompt()`)"
     ]
   )
 
@@ -119,4 +132,26 @@ defmodule PhoenixTest.Playwright.Config do
 
   defp normalize(:screenshot, true), do: NimbleOptions.validate!([], @screenshot_opts_schema)
   defp normalize(_key, value), do: value
+
+  def __validate_runner__(runner) do
+    if executable = System.find_executable(runner) do
+      {:ok, executable}
+    else
+      message = """
+      could not find runner executable at `#{runner}`.
+
+      To resolve this please
+      1. Install a JS package runner like `npx` or `bunx`
+      2. Configure the preferred runner in `config/test.exs`, e.g.: `config :phoenix_test, playwright: [runner: "npx"]`
+      3. Ensure either the runner is in your PATH or the `runner` value is a absolute path to the executable (e.g. `Path.absname("_build/bun")`)
+      """
+
+      {:error, message}
+    end
+  end
+
+  def __validate_cli__(_cli) do
+    {:error,
+     "it is deprecated. Use `assets_dir` instead if you want to customize the Playwright installation directory path and remove the `cli` option."}
+  end
 end

lib/phoenix_test/playwright/port.ex

@@ -15,26 +15,14 @@ defmodule PhoenixTest.Playwright.Port do
     :buffer
   ]
 
-  def cli_path do
-    path = Config.global(:cli)
-
-    if !File.exists?(path) do
-      msg = """
-      Could not find playwright CLI at #{path}.
-
-      To resolve this please
-      1. Install playwright, e.g. `npm i playwright`
-      2. Configure the path correctly, e.g. in `config/test.exs`: `config :phoenix_test, playwright: [cli: "assets/node_modules/playwright/cli.js"]`
-      """
-
-      raise ArgumentError, msg
-    end
-
-    path
-  end
-
   def open do
-    port = Port.open({:spawn, "#{cli_path()} run-driver"}, [:binary])
+    port =
+      Port.open({:spawn_executable, Config.global(:runner)}, [
+        :binary,
+        args: ["playwright", "run-driver"],
+        cd: Config.global(:assets_dir)
+      ])
+
     %__MODULE__{port: port, remaining: 0, buffer: ""}
   end