And CI API endpoint where user can erase a build

app/views/projects/builds/show.html.haml

@@ -83,7 +83,8 @@
               = raw @build.trace_html
       - else
         .erased.alert.alert-warning
-          Build has been erased by #{@build.erased_by.username} #{time_ago_with_tooltip(@build.created_at)}
+          - erased_by = "by #{@build.erased_by.username}" if @build.erased_by
+          Build has been erased #{erased_by} #{time_ago_with_tooltip(@build.created_at)}
 
       %div#down-build-trace
 

features/steps/project/builds/summary.rb

@@ -26,6 +26,8 @@ class Spinach::Features::ProjectBuildsSummary < Spinach::FeatureSteps
   end
 
   step 'recent build summary contains information saying that build has been erased' do
-    expect(page).to have_css('.erased')
+    page.within('.erased') do
+      expect(page).to have_content 'Build has been erased'
+    end
   end
 end

lib/ci/api/builds.rb

@@ -159,6 +159,22 @@ module Ci
           build.remove_artifacts_file!
           build.remove_artifacts_metadata!
         end
+
+        # Erase build (remove artifacts and build trace)
+        #
+        # Parameters:
+        #   id (required) - The ID of a build
+        #   token (required) - The build authorization token
+        # Headers:
+        #   BUILD-TOKEN (required) - The build authorization token, the same as token
+        # Example Request:
+        #   PUT /builds/:id/erase
+        put ':id/erase' do
+          build = Ci::Build.find_by_id(params[:id])
+          not_found! unless build
+          authenticate_build_token!(build)
+          build.erase!
+        end
       end
     end
   end