Provide a link to existing domain block when trying to block an already-blocked domain (#10663)

* When trying to block an already-blocked domain, provide a link to the block

* Fix styling for links in flash messages

* Allow blocks to be upgraded but not downgraded

spec/controllers/admin/domain_blocks_controller_spec.rb

@@ -37,7 +37,7 @@ RSpec.describe Admin::DomainBlocksController, type: :controller do
     end
 
     it 'renders new when failed to save' do
-      Fabricate(:domain_block, domain: 'example.com')
+      Fabricate(:domain_block, domain: 'example.com', severity: 'suspend')
       allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
 
       post :create, params: { domain_block: { domain: 'example.com', severity: 'silence' } }
@@ -45,6 +45,17 @@ RSpec.describe Admin::DomainBlocksController, type: :controller do
       expect(DomainBlockWorker).not_to have_received(:perform_async)
       expect(response).to render_template :new
     end
+
+    it 'allows upgrading a block' do
+      Fabricate(:domain_block, domain: 'example.com', severity: 'silence')
+      allow(DomainBlockWorker).to receive(:perform_async).and_return(true)
+
+      post :create, params: { domain_block: { domain: 'example.com', severity: 'silence', reject_media: true, reject_reports: true } }
+
+      expect(DomainBlockWorker).to have_received(:perform_async)
+      expect(flash[:notice]).to eq I18n.t('admin.domain_blocks.created_msg')
+      expect(response).to redirect_to(admin_instances_path(limited: '1'))
+    end
   end
 
   describe 'DELETE #destroy' do

spec/models/domain_block_spec.rb

@@ -36,4 +36,35 @@ RSpec.describe DomainBlock, type: :model do
       expect(DomainBlock.blocked?('domain')).to eq false
     end
   end
+
+  describe 'stricter_than?' do
+    it 'returns true if the new block has suspend severity while the old has lower severity' do
+      suspend = DomainBlock.new(domain: 'domain', severity: :suspend)
+      silence = DomainBlock.new(domain: 'domain', severity: :silence)
+      noop = DomainBlock.new(domain: 'domain', severity: :noop)
+      expect(suspend.stricter_than?(silence)).to be true
+      expect(suspend.stricter_than?(noop)).to be true
+    end
+
+    it 'returns false if the new block has lower severity than the old one' do
+      suspend = DomainBlock.new(domain: 'domain', severity: :suspend)
+      silence = DomainBlock.new(domain: 'domain', severity: :silence)
+      noop = DomainBlock.new(domain: 'domain', severity: :noop)
+      expect(silence.stricter_than?(suspend)).to be false
+      expect(noop.stricter_than?(suspend)).to be false
+      expect(noop.stricter_than?(silence)).to be false
+    end
+
+    it 'returns false if the new block does is less strict regarding reports' do
+      older = DomainBlock.new(domain: 'domain', severity: :silence, reject_reports: true)
+      newer = DomainBlock.new(domain: 'domain', severity: :silence, reject_reports: false)
+      expect(newer.stricter_than?(older)).to be false
+    end
+
+    it 'returns false if the new block does is less strict regarding media' do
+      older = DomainBlock.new(domain: 'domain', severity: :silence, reject_media: true)
+      newer = DomainBlock.new(domain: 'domain', severity: :silence, reject_media: false)
+      expect(newer.stricter_than?(older)).to be false
+    end
+  end
 end