Add nav link for Instance Security Dashboard

This adds a nav link for the [Instance Security Dashboard MVC][1], which
is behind the `security_dashboard` feature flag.

This also refactors slightly how the visibility of the Operations and
Environments dashboard links is handled. One result of this is that they
are now consistently visible/hidden between the dashboards dropdown on
larger screens, and the "More" dropdown on smaller screens.

Finally, the partials have been renamed, since they're no longer
specific to operations.

[1]: https://gitlab.com/gitlab-org/gitlab/issues/6953

app/views/layouts/nav/_dashboard.html.haml

@@ -59,7 +59,7 @@
           = render_if_exists 'layouts/nav/sidebar/analytics_more_link'
 
           %li.dropdown.d-lg-none
-            = render_if_exists 'dashboard/operations/nav_link_list'
+            = render_if_exists 'dashboard/nav_link_list'
           - if can?(current_user, :read_instance_statistics)
             = nav_link(controller: [:conversational_development_index, :cohorts], html_options: { class: 'd-lg-none' }) do
               = link_to instance_statistics_root_path do
@@ -86,7 +86,7 @@
           = _('Web IDE')
 
   %li.dropdown{ class: 'd-none d-lg-block' }
-    = render_if_exists 'dashboard/operations/nav_link'
+    = render_if_exists 'dashboard/nav_link'
   - if can?(current_user, :read_instance_statistics)
     = nav_link(controller: [:conversational_development_index, :cohorts], html_options: { class: "d-none d-lg-block d-xl-block"}) do
       = link_to instance_statistics_root_path, title: _('Instance Statistics'), aria: { label: _('Instance Statistics') }, data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do

ee/app/helpers/ee/dashboard_helper.rb

@@ -37,6 +37,15 @@ module EE
     def get_dashboard_nav_links
       super.tap do |links|
         links << :analytics if ::Gitlab::Analytics.any_features_enabled?
+
+        if can?(current_user, :read_operations_dashboard)
+          links << :environments if ::Feature.enabled?(:environments_dashboard)
+          links << :operations
+        end
+
+        if ::Feature.enabled?(:security_dashboard) && can?(current_user, :read_security_dashboard)
+          links << :security
+        end
       end
     end
   end

ee/app/views/dashboard/operations/_nav_link.html.haml → ee/app/views/dashboard/_nav_link.html.haml

-- if can?(current_user, :read_operations_dashboard)
-  %button#js-dashboards-menu.btn-link{ type: 'button', data: { toggle: 'dropdown' }, 'aria-label': _('Operations Dashboard'), 'aria-haspopup': true, 'aria-expanded': false }
+- if any_dashboard_nav_link?([:environments, :operations, :security])
+  %button#js-dashboards-menu.btn-link{ type: 'button', data: { toggle: 'dropdown' }, 'aria-label': _('Dashboards'), 'aria-haspopup': true, 'aria-expanded': false }
     = sprite_icon('dashboard', size: 18)
     = sprite_icon('angle-down', css_class: 'caret-down')
   .dropdown-menu{ 'aria-labelledby': "js-dashboards-menu" }
     .dropdown-bold-header
       = _('Dashboards')
-    = render_if_exists 'dashboard/operations/nav_link_list'
+    = render_if_exists 'dashboard/nav_link_list'

ee/app/views/dashboard/_nav_link_list.html.haml

+- if dashboard_nav_link?(:environments)
+  = link_to operations_environments_path, class: 'dropdown-item' do
+    = _('Environments')
+- if dashboard_nav_link?(:operations)
+  = link_to operations_path, class: 'dropdown-item' do
+    = _('Operations')
+- if dashboard_nav_link?(:security)
+  = link_to security_path, class: 'dropdown-item' do
+    = _('Security')

ee/app/views/dashboard/operations/_nav_link_list.html.haml

-- if Feature.enabled?('environments_dashboard')
-  = link_to operations_environments_path, class: 'dropdown-item' do
-    = _('Environments')
-= link_to operations_path, class: 'dropdown-item' do
-  = _('Operations')

ee/spec/helpers/ee/dashboard_helper_spec.rb

@@ -7,29 +7,69 @@ describe DashboardHelper, type: :helper do
 
   let(:user) { build(:user) }
 
-  before do
-    allow(helper).to receive(:current_user).and_return(user)
-    allow(helper).to receive(:can?) { true }
-  end
-
   describe '#dashboard_nav_links' do
-    context 'when at least one analytics feature is enabled' do
+    before do
+      allow(helper).to receive(:current_user).and_return(user)
+    end
+
+    describe 'analytics' do
       before do
-        enable_only_one_analytics_feature_flag
+        allow(helper).to receive(:can?) { true }
       end
 
-      it 'includes analytics' do
-        expect(helper.dashboard_nav_links).to include(:analytics)
+      context 'when at least one analytics feature is enabled' do
+        before do
+          enable_only_one_analytics_feature_flag
+        end
+
+        it 'includes analytics' do
+          expect(helper.dashboard_nav_links).to include(:analytics)
+        end
+      end
+
+      context 'when all analytics features are disabled' do
+        before do
+          disable_all_analytics_feature_flags
+        end
+
+        it 'does not include analytics' do
+          expect(helper.dashboard_nav_links).not_to include(:analytics)
+        end
       end
     end
 
-    context 'when all analytics features are disabled' do
-      before do
-        disable_all_analytics_feature_flags
+    describe 'operations, environments and security' do
+      using RSpec::Parameterized::TableSyntax
+
+      where(:ability, :feature_flag, :nav_link) do
+        :read_operations_dashboard | nil                     | :operations
+        :read_operations_dashboard | :environments_dashboard | :environments
+        :read_security_dashboard   | :security_dashboard     | :security
       end
 
-      it 'does not include analytics' do
-        expect(helper.dashboard_nav_links).not_to include(:analytics)
+      with_them do
+        describe 'when the feature is enabled' do
+          before do
+            stub_feature_flags(feature_flag => true) unless feature_flag.nil?
+            allow(helper).to receive(:can?).and_return(false)
+            allow(helper).to receive(:can?).with(user, ability).and_return(true)
+          end
+
+          it 'includes the nav link' do
+            expect(helper.dashboard_nav_links).to include(nav_link)
+          end
+        end
+
+        describe 'when the feature is disabled' do
+          before do
+            stub_feature_flags(feature_flag => false) unless feature_flag.nil?
+            allow(helper).to receive(:can?).and_return(false)
+          end
+
+          it 'does not include the nav link' do
+            expect(helper.dashboard_nav_links).not_to include(nav_link)
+          end
+        end
       end
     end
   end