Add assert_component_rendered test helper (#2066)

* add assert_component_rendered

* fix linting

* update docs

* docs cleanup

* fix docs typo

---------

Co-authored-by: Joel Hawksley <[email protected]>
Co-authored-by: Joel Hawksley <[email protected]>

Author: reeganviljoen

docs/CHANGELOG.md

@@ -22,6 +22,10 @@ nav_order: 5
 
     *Seth Herr*
 
+* Add `assert_component_rendered` test helper.
+
+    *Reegan Viljoen*
+
 * Add `prefix:` option to `use_helpers`.
 
     *Reegan Viljoen*

docs/guide/conditional_rendering.md

@@ -51,4 +51,4 @@ end
 <%= render(ConfirmEmailComponent.new(user: current_user)) %>
 ```
 
-_To assert that a component hasn't been rendered, use `refute_component_rendered` from `ViewComponent::TestHelpers`._
+_To assert whether a component has been rendered, use `assert_component_rendered` / `refute_component_rendered` from `ViewComponent::TestHelpers`._

docs/guide/getting-started.md

@@ -126,5 +126,5 @@ end
 To render ViewComponents outside of the view context (such as in a background job, markdown processor, etc), instantiate a Rails controller:
 
 ```ruby
-ApplicationComponent.new.view_context.render(MyComponent.new)
+ApplicationController.new.view_context.render(MyComponent.new)
 ```

docs/guide/testing.md

@@ -15,6 +15,8 @@ class ExampleComponentTest < ViewComponent::TestCase
   def test_render_component
     render_inline(ExampleComponent.new(title: "my title")) { "Hello, World!" }
 
+    assert_component_rendered
+
     assert_selector("span[title='my title']", text: "Hello, World!")
     # or, to just assert against the text:
     assert_text("Hello, World!")

lib/view_component/test_helpers.rb

@@ -14,6 +14,10 @@ def page
       def refute_component_rendered
         assert_no_selector("body")
       end
+
+      def assert_component_rendered
+        assert_selector("body")
+      end
     rescue LoadError
       # We don't have a test case for running an application without capybara installed.
       # It's probably fine to leave this without coverage.

test/sandbox/test/rendering_test.rb

@@ -400,6 +400,7 @@ def test_conditional_rendering_if_content_provided
       "Content"
     end
 
+    assert_component_rendered
     assert_text("Content")
   end