Remove static HAML fixtures from frontend testing guide

(cherry picked from commit 26cba3b05fbf02e97bb6504382654209af4f8e78)

doc/development/testing_guide/frontend_testing.md

@@ -53,12 +53,9 @@ Remember that the performance of each test depends on the environment.
 ## Karma test suite
 
 GitLab uses the [Karma][karma] test runner with [Jasmine] as its test
-framework for our JavaScript unit and integration tests. For integration tests,
-we generate HTML files using RSpec (see `spec/javascripts/fixtures/*.rb` for examples).
-Some fixtures are still HAML templates that are translated to HTML files using the same mechanism (see `static_fixtures.rb`).
-Adding these static fixtures should be avoided as they are harder to keep up to date with real views.
-The existing static fixtures will be migrated over time.
-Please see [gitlab-org/gitlab-ce#24753](https://gitlab.com/gitlab-org/gitlab-ce/issues/24753) to track our progress.
+framework for our JavaScript unit and integration tests.
+We generate HTML and JSON fixtures from backend views and controllers
+using RSpec (see `spec/javascripts/fixtures/*.rb` for examples).
 Fixtures are served during testing by the [jasmine-jquery][jasmine-jquery] plugin.
 
 JavaScript tests live in `spec/javascripts/`, matching the folder structure

spec/javascripts/fixtures/static/README.md

+# Please do not add new files here!
+
+Instead use a Ruby file in the fixtures root directory (`spec/javascripts/fixtures/`).