Handle form redirects in Static pages (#22)

What changed?
============

Commit 531e5e9 updated Live form submissions to follow redirects to
other LiveView and Static pages.

This commit does the same but for Static pages.

Thus, now when a `fill_form` + `click_button`, a single-field form
`click_button`, or a `submit_button` redirects, we follow the redirect
to the other page -- whether that be a LiveView or a static page.

lib/phoenix_test/static.ex

@@ -84,9 +84,9 @@ defimpl PhoenixTest.Driver, for: PhoenixTest.Static do
 
     data = form["data"]
 
-    conn = dispatch(session.conn, @endpoint, method, action, data)
-
-    %{session | conn: conn}
+    session.conn
+    |> dispatch(@endpoint, method, action, data)
+    |> maybe_redirect(session)
   end
 
   defp single_button_form_submit(session, text) do
@@ -98,9 +98,9 @@ defimpl PhoenixTest.Driver, for: PhoenixTest.Static do
     action = Html.attribute(form, "action")
     method = Html.attribute(form, "method") || "get"
 
-    conn = dispatch(session.conn, @endpoint, method, action)
-
-    %{session | conn: conn}
+    session.conn
+    |> dispatch(@endpoint, method, action)
+    |> maybe_redirect(session)
   end
 
   def submit_form(session, selector, form_data) do
@@ -123,6 +123,22 @@ defimpl PhoenixTest.Driver, for: PhoenixTest.Static do
     |> PhoenixTest.Static.put_private(:active_form, form)
   end
 
+  def render_html(%{conn: conn}) do
+    conn
+    |> html_response(200)
+  end
+
+  defp maybe_redirect(conn, session) do
+    case conn do
+      %{status: 302} ->
+        path = redirected_to(conn)
+        PhoenixTest.visit(conn, path)
+
+      %{status: _} ->
+        %{session | conn: conn}
+    end
+  end
+
   defp verify_expected_form_data(form, form_data) do
     action = form["action"]
     unless action, do: raise("Expected form to have an action but found none")
@@ -144,6 +160,13 @@ defimpl PhoenixTest.Driver, for: PhoenixTest.Static do
     end)
   end
 
+  defp verify_field_presence([], expected_field) do
+    raise ArgumentError, """
+    Expected form to have #{inspect(expected_field)} form field, but found no
+    existing fields.
+    """
+  end
+
   defp verify_field_presence(existing_fields, expected_field) do
     if Enum.all?(existing_fields, fn field ->
          field["name"] != expected_field
@@ -161,9 +184,4 @@ defimpl PhoenixTest.Driver, for: PhoenixTest.Static do
   defp format_field_error(field) do
     "#{field["type"]} with name=#{inspect(field["name"])}"
   end
-
-  def render_html(%{conn: conn}) do
-    conn
-    |> html_response(200)
-  end
 end

test/phoenix_test/static_test.exs

@@ -98,6 +98,13 @@ defmodule PhoenixTest.StaticTest do
       |> assert_has("h1", "Record deleted")
     end
 
+    test "can handle redirects to a LiveView", %{conn: conn} do
+      conn
+      |> visit("/page/index")
+      |> click_button("Post and Redirect")
+      |> assert_has("h1", "LiveView main page")
+    end
+
     test "raises an error when there are no buttons on page", %{conn: conn} do
       assert_raise ArgumentError, ~r/Could not find an element with given selector/, fn ->
         conn
@@ -116,6 +123,32 @@ defmodule PhoenixTest.StaticTest do
   end
 
   describe "fill_form/3" do
+    test "raises an error when form cannot be found with given selector", %{conn: conn} do
+      assert_raise ArgumentError, ~r/Could not find element with selector/, fn ->
+        conn
+        |> visit("/page/index")
+        |> fill_form("#no-existing-form", name: "Aragorn")
+      end
+    end
+
+    test "raises an error when form input cannot be found", %{conn: conn} do
+      message = """
+      Expected form to have "location[user][name]" form field, but found none.
+
+      Found the following fields:
+
+       - input with name="user[name]"
+      """
+
+      assert_raise ArgumentError, message, fn ->
+        conn
+        |> visit("/page/index")
+        |> fill_form("#nested-form", location: %{user: %{name: "Aragorn"}})
+      end
+    end
+  end
+
+  describe "fill_form + click_button" do
     test "can submit forms with input type submit", %{conn: conn} do
       conn
       |> visit("/page/index")
@@ -150,28 +183,12 @@ defmodule PhoenixTest.StaticTest do
       |> assert_has("#form-data", "member_of_fellowship: on")
     end
 
-    test "raises an error when form cannot be found with given selector", %{conn: conn} do
-      assert_raise ArgumentError, ~r/Could not find element with selector/, fn ->
-        conn
-        |> visit("/page/index")
-        |> fill_form("#no-existing-form", name: "Aragorn")
-      end
-    end
-
-    test "raises an error when form input cannot be found", %{conn: conn} do
-      message = """
-      Expected form to have "location[user][name]" form field, but found none.
-
-      Found the following fields:
-
-       - input with name="user[name]"
-      """
-
-      assert_raise ArgumentError, message, fn ->
-        conn
-        |> visit("/page/index")
-        |> fill_form("#nested-form", location: %{user: %{name: "Aragorn"}})
-      end
+    test "can handle redirects into a LiveView", %{conn: conn} do
+      conn
+      |> visit("/page/index")
+      |> fill_form("#redirect-to-liveview-form", name: "Aragorn")
+      |> click_button("Save and Redirect to LiveView")
+      |> assert_has("h1", "LiveView main page")
     end
   end
 
@@ -183,6 +200,13 @@ defmodule PhoenixTest.StaticTest do
       |> assert_has("#form-data", "name: Aragorn")
     end
 
+    test "can handle redirects", %{conn: conn} do
+      conn
+      |> visit("/page/index")
+      |> submit_form("#no-submit-button-and-redirect", name: "Aragorn")
+      |> assert_has("h1", "LiveView main page")
+    end
+
     test "raises an error if the form can't be found", %{conn: conn} do
       assert_raise ArgumentError, ~r/Could not find element with selector/, fn ->
         conn

test/support/page_controller.ex

@@ -23,4 +23,9 @@ defmodule PhoenixTest.PageController do
     conn
     |> render("record_deleted.html")
   end
+
+  def redirect_to_liveview(conn, _) do
+    conn
+    |> redirect(to: "/live/index")
+  end
 end

test/support/page_view.ex

@@ -74,6 +74,21 @@ defmodule PhoenixTest.PageView do
         <input type="checkbox" name="member_of_fellowship" />
       </div>
     </form>
+
+    <form id="redirect-to-liveview-form" method="post" action="/page/redirect_to_liveview">
+      <label for="name">Name</label>
+      <input name="name" />
+      <button type="submit">Save and Redirect to LiveView</button>
+    </form>
+
+    <form method="post" action="/page/redirect_to_liveview">
+      <button>Post and Redirect</button>
+    </form>
+
+    <form id="no-submit-button-and-redirect" method="post" action="/page/redirect_to_liveview">
+      <label for="name">Name</label>
+      <input name="name" />
+    </form>
     """
   end
 

test/support/router.ex

@@ -29,6 +29,7 @@ defmodule PhoenixTest.Router do
     put "/page/update_record", PageController, :update
     delete "/page/delete_record", PageController, :delete
     get "/page/:page", PageController, :show
+    post "/page/redirect_to_liveview", PageController, :redirect_to_liveview
 
     live_session :live_pages do
       live "/live/index", IndexLive