add disconnected coverage

spec/outboxer/publisher/disconnect_spec.rb

@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+module Outboxer
+  RSpec.describe Publisher do
+    describe '.disconnect!' do
+      context 'when successful' do
+        it 'does not raise an error' do
+          expect { Publisher.disconnect! }.not_to raise_error
+        end
+
+        it 'returns connected false' do
+          Publisher.disconnect!
+
+          expect(Publisher.connected?).to be false
+        end
+      end
+
+      context 'when not successful' do
+        before do
+          allow(ActiveRecord::Base.connection_handler)
+            .to receive(:clear_active_connections!).and_raise(ActiveRecord::ConnectionNotEstablished)
+        end
+
+        it 'raises a DisconnectError' do
+          expect { Publisher.disconnect! }.to raise_error(Publisher::DisconnectError)
+        end
+      end
+    end
+  end
+end