Fix 500 error when visit group from admin area if group name contains dot

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

changelogs/unreleased/dz-improve-admin-group-routing.yml

+---
+title: Fix 500 error when visit group from admin area if group name contains dot
+merge_request:
+author:

config/routes/admin.rb

@@ -32,7 +32,7 @@ namespace :admin do
 
   scope(path: 'groups/*id',
         controller: :groups,
-        constraints: { id: Gitlab::Regex.namespace_route_regex }) do
+        constraints: { id: Gitlab::Regex.namespace_route_regex, format: /(html|json|atom)/ }) do
 
     scope(as: :group) do
       put :members_update

spec/routing/admin_routing_spec.rb

@@ -122,12 +122,18 @@ describe Admin::HealthCheckController, "routing" do
 end
 
 describe Admin::GroupsController, "routing" do
+  let(:name) { 'complex.group-namegit' }
+
   it "to #index" do
     expect(get("/admin/groups")).to route_to('admin/groups#index')
   end
 
   it "to #show" do
-    expect(get("/admin/groups/gitlab")).to route_to('admin/groups#show', id: 'gitlab')
-    expect(get("/admin/groups/gitlab/subgroup")).to route_to('admin/groups#show', id: 'gitlab/subgroup')
+    expect(get("/admin/groups/#{name}")).to route_to('admin/groups#show', id: name)
+    expect(get("/admin/groups/#{name}/subgroup")).to route_to('admin/groups#show', id: "#{name}/subgroup")
+  end
+
+  it "to #edit" do
+    expect(get("/admin/groups/#{name}/edit")).to route_to('admin/groups#edit', id: name)
   end
 end