Phoenix.LiveViewTest.render_component

You're seeing just the macro render_component, go back to Phoenix.LiveViewTest module for more information.
Link to this macro

render_component(component, assigns, opts \\ [])

View Source (macro)

Mounts, updates and renders a component.

If the component uses the @myself assigns, then an id must be given to it is marked as stateful.

Examples

assert render_component(MyComponent, id: 123, user: %User{}) =~
         "some markup in component"

assert render_component(MyComponent, %{id: 123, user: %User{}}, router: SomeRouter) =~
         "some markup in component"