Extend composer specs to cover group visibility

Extend composer specs to test for auth token
from private token param

changelogs/unreleased/232636-add-support-for-fixing-composer-404.yml

+---
+title: Fix composer 404 issues with http auth
+merge_request: 38641
+author:
+type: fixed

doc/user/packages/composer_repository/index.md

@@ -130,11 +130,8 @@ You also need to create a `auth.json` file with your GitLab credentials:
 
 ```json
 {
-    "http-basic": {
-        "gitlab.com": {
-            "username": "___token___",
-            "password": "<personal_access_token>"
-        }
+    "gitlab-token": {
+       "gitlab.com": "<personal_access_token>"
     }
 }
 ```

spec/support/shared_examples/requests/api/composer_packages_shared_examples.rb

@@ -16,8 +16,11 @@ RSpec.shared_examples 'Composer package index' do |user_type, status, add_member
       subject
 
       expect(response).to have_gitlab_http_status(status)
-      expect(response).to match_response_schema('public_api/v4/packages/composer/index')
-      expect(json_response).to eq presenter.root
+
+      if status == :success
+        expect(response).to match_response_schema('public_api/v4/packages/composer/index')
+        expect(json_response).to eq presenter.root
+      end
     end
   end
 end
@@ -87,13 +90,22 @@ RSpec.shared_examples 'process Composer api request' do |user_type, status, add_
   end
 end
 
-RSpec.shared_context 'Composer auth headers' do |user_role, user_token|
+RSpec.shared_context 'Composer auth headers' do |user_role, user_token, auth_method = :token|
   let(:token) { user_token ? personal_access_token.token : 'wrong' }
-  let(:headers) { user_role == :anonymous ? {} : basic_auth_header(user.username, token) }
+
+  let(:headers) do
+    if user_role == :anonymous
+      {}
+    elsif auth_method == :token
+      { 'Private-Token' => token }
+    else
+      basic_auth_header(user.username, token)
+    end
+  end
 end
 
-RSpec.shared_context 'Composer api project access' do |project_visibility_level, user_role, user_token|
-  include_context 'Composer auth headers', user_role, user_token do
+RSpec.shared_context 'Composer api project access' do |project_visibility_level, user_role, user_token, auth_method|
+  include_context 'Composer auth headers', user_role, user_token, auth_method do
     before do
       project.update!(visibility_level: Gitlab::VisibilityLevel.const_get(project_visibility_level, false))
     end