FEATURE: Allow posting via email to read-only mailing list mirror category

spec/components/email/receiver_spec.rb

@@ -798,12 +798,12 @@ describe Email::Receiver do
     end
   end
 
-  context "mailinglist mirror" do
+  context "mailing list mirror" do
+    let!(:category) { Fabricate(:mailinglist_mirror_category) }
+
     before do
       SiteSetting.block_auto_generated_emails = true
       SiteSetting.find_related_post_with_key = true
-
-      Fabricate(:mailinglist_mirror_category)
     end
 
     it "should allow creating topic even when email is autogenerated" do
@@ -817,5 +817,26 @@ describe Email::Receiver do
 
       expect { process(:mailinglist_reply) }.to change { topic.posts.count }
     end
+
+    context "read-only category" do
+      before do
+        category.set_permissions(everyone: :readonly)
+        category.save
+
+        Fabricate(:user, email: "alice@foo.com")
+        Fabricate(:user, email: "bob@bar.com")
+      end
+
+      it "should allow creating topic within read-only category" do
+        expect { process(:mailinglist) }.to change { Topic.count }
+      end
+
+      it "should allow replying within read-only category" do
+        process(:mailinglist)
+        topic = Topic.last
+
+        expect { process(:mailinglist_reply) }.to change { topic.posts.count }
+      end
+    end
   end
 end