Add tests and changelog item for language graphs

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

CHANGELOG

@@ -17,6 +17,7 @@ v 8.3.0 (unreleased)
   - Fix: Ensure "Remove Source Branch" button is not shown when branch is being deleted. #3583
   - Run custom Git hooks when branch is created or deleted.
   - Fix bug when simultaneously accepting multiple MRs results in MRs that are of "merged" status, but not merged to the target branch
+  - Add languages page to graphs
 
 v 8.2.3
   - Fix application settings cache not expiring after changes (Stan Hu)

features/project/graph.feature

@@ -18,3 +18,8 @@ Feature: Project Graph
     Given project "Shop" has CI enabled
     When I visit project "Shop" CI graph page
     Then page should have CI graphs
+
+  @javascript
+  Scenario: I should see project languages graphs
+    When I visit project "Shop" languages graph page
+    Then page should have languages graphs

features/steps/project/graph.rb

@@ -14,6 +14,15 @@ class Spinach::Features::ProjectGraph < Spinach::FeatureSteps
     visit commits_namespace_project_graph_path(project.namespace, project, "master")
   end
 
+  step 'I visit project "Shop" languages graph page' do
+    visit languages_namespace_project_graph_path(project.namespace, project, "master")
+  end
+
+  step 'page should have languages graphs' do
+    expect(page).to have_content "Ruby 66.63 %"
+    expect(page).to have_content "JavaScript 22.96 %"
+  end
+
   step 'page should have commits graphs' do
     expect(page).to have_content "Commit statistics for master"
     expect(page).to have_content "Commits per day of month"