test: cover FormForHelperTest, persisted?

test/test_form_for_helper.rb

@@ -0,0 +1,83 @@
+require 'minitest/autorun'
+require 'prism'
+
+class FormForHelperTest < Minitest::Test
+  FakeModel = Struct.new(:id, :title) do
+    def persisted?
+      !id.nil?
+    end
+  end
+
+  HelpersWithCsrf = Struct.new(:csrf_token)
+
+  def render(source, helpers = nil)
+    Prism::Template.render(source, {}, nil, helpers)
+  end
+
+  def test_form_for_new_record_uses_post
+    html = render(<<~ERB)
+      <% form_for(FormForHelperTest::FakeModel.new,  url: "/posts") do |f| %>
+      <%== f.text_field(:title) %>
+      <% end  %>
+    ERB
+    assert_includes html, '<form action="/posts" method="post">'
+    refute_includes html, '_method'
+    assert_includes html, 'name="fake_model[title]"'
+    assert_includes html, '</form>'
+  end
+
+  def test_form_for_persisted_record_defaults_to_patch_via_method_override
+    html = render(<<~ERB)
+      <% form_for(FormForHelperTest::FakeModel.new(1, "hi"), url: "/posts/1") do |f| %>
+      <%== f.submit %>
+      <% end %>
+    ERB
+    assert_includes html, '<form action="/posts/1" method="post">'
+    assert_includes html, '<input type="hidden" name="_method" value="PATCH">'
+  end
+
+  def test_form_for_explicit_method_delete
+    html = render(<<~ERB)
+      <% form_for(FormForHelperTest::FakeModel.new, url: "/posts/1", method: :delete) do |f| %>
+      <% end %>
+    ERB
+    assert_includes html, '<input type="hidden" name="_method" value="DELETE">'
+  end
+
+  def test_form_for_embeds_csrf_token_when_helpers_provide_one
+    helpers = HelpersWithCsrf.new('secrettoken')
+    html = render(<<~ERB, helpers)
+      <% form_for(FormForHelperTest::FakeModel.new, url: "/posts") do |f| %>
+      <% end %>
+    ERB
+    assert_includes html, '<input type="hidden" name="authenticity_token" value="secrettoken">'
+  end
+
+  def test_form_for_without_helpers_has_no_csrf_field
+    html = render(<<~ERB)
+      <% form_for(FormForHelperTest::FakeModel.new, url: "/posts") do |f| %>
+      <% end %>
+    ERB
+    refute_includes html, 'authenticity_token'
+  end
+
+  def test_form_for_get_has_no_csrf_field
+    helpers = HelpersWithCsrf.new('secrettoken')
+    html = render(<<~ERB, helpers)
+      <% form_for(FormForHelperTest::FakeModel.new, url: "/posts", method: :get) do |f| %>
+      <% end %>
+    ERB
+    refute_includes html, 'authenticity_token'
+  end
+
+  def test_content_between_form_fields_is_placed_in_order
+    html = render(<<~ERB)
+      <% form_for(FormForHelperTest::FakeModel.new, url: "/posts") do |f| %>
+      <%== f.label(:title) %>
+      <%== f.text_field(:title) %>
+      <% end %>
+    ERB
+    assert html.index('<label') < html.index('<input')
+    assert html.index('<input') < html.index('</form>')
+  end
+end