correct flaky spec

spec/components/discourse_redis_spec.rb

@@ -102,20 +102,6 @@ describe DiscourseRedis do
       expect(connector.resolve).to eq(config)
     end
 
-    it 'should return the slave config when master is down' do
-      begin
-        Redis::Client.any_instance.expects(:call).raises(Redis::CannotConnectError).once
-        expect { connector.resolve }.to raise_error(Redis::CannotConnectError)
-
-        config = connector.resolve
-
-        expect(config[:host]).to eq(slave_host)
-        expect(config[:port]).to eq(slave_port)
-      ensure
-        fallback_handler.master = true
-      end
-    end
-
     class BrokenRedis
       def initialize(error)
         @error = error
@@ -129,6 +115,20 @@ describe DiscourseRedis do
       end
     end
 
+    it 'should return the slave config when master is down' do
+      begin
+        error = Redis::CannotConnectError
+        expect { connector.resolve(BrokenRedis.new(error)) }.to raise_error(Redis::CannotConnectError)
+
+        config = connector.resolve
+
+        expect(config[:host]).to eq(slave_host)
+        expect(config[:port]).to eq(slave_port)
+      ensure
+        fallback_handler.master = true
+      end
+    end
+
     it "should return the slave config when master's hostname cannot be resolved" do
       begin
         error = RuntimeError.new('Name or service not known')