Allow coaches to access all communities

This is a fix for pupilfirst#506.

app/queries/topics_resolver.rb

@@ -22,9 +22,9 @@ def authorized?
 
     return false if community.school_id != current_school.id
 
-    course_ids = ([current_user.faculty&.course_ids] + [current_user.course_ids]).flatten
+    return true if current_user.faculty.present? || current_school_admin.present?
 
-    (course_ids & community.course_ids).present? || current_school_admin.present?
+    (current_user.course_ids & community.course_ids).present?
   end
 
   def title_for_search

spec/system/community/community_spec.rb

@@ -45,6 +45,14 @@
     expect(page).to have_text('Please sign in to continue.')
   end
 
+  scenario 'student from an unlinked course attempts to visit community' do
+    CommunityCourseConnection.where(course: course).destroy_all
+
+    sign_in_user(student_1.user, referrer: community_path(community))
+
+    expect(page).to have_text("The page you were looking for doesn't exist")
+  end
+
   scenario 'an active student visits his community' do
     sign_in_user(student_1.user, referrer: community_path(community))
 
@@ -641,4 +649,24 @@
       expect(find("#topics a:nth-child(1)")).to have_content(topic_2.title)
     end
   end
+
+  context "when the user is a coach who isn't enrolled in one of the community's connected courses" do
+    before do
+      CommunityCourseConnection.destroy_all
+    end
+
+    scenario "a coach from a different course can still moderate on unlinked communities" do
+      sign_in_user(coach.user, referrer: community_path(community))
+
+      click_link topic_1.title
+
+      # Can mark a reply as solution.
+      find("div[aria-label='Options for post #{reply_1.id}']").click
+      click_button 'Mark as solution'
+
+      within("div#post-show-#{reply_1.id}") do
+        expect(page).to have_selector("div[aria-label='Marked as solution icon']")
+      end
+    end
+  end
 end