Using 'localhost' makes tests run 10x slower

[TroyWalshProf]

If I use "http://127.0.0.1:4723" as the remote address when running tests locally, my test run fairly fast.
However, if I use 'http://localhost:4723' all my interactions are extremely slow, and my test execution time goes way up. - All interactions take about 10 times as long.

Sample test code:
https://github.com/Magenic/MAQS/blob/master/Framework/AppiumUnitTests/AppiumWinAppUnitTests.cs#L30
Line to change remote address:
https://github.com/Magenic/MAQS/blob/master/Framework/AppiumUnitTests/AppiumWinAppUnitTests.cs#L56

[Wolfe1]

Hmmm I tried replicating on my end using this same code: https://github.com/Accruent/robotframework-zoomba/blob/master/samples/DesktopTests.robot (I work in python/robotframework) and I am not getting any noticeable difference between the two (average over 3 runs each).

How many lines do you have in your Windows Hosts file (aside from the commented out bits):
C:\Windows\System32\Drivers\etc\hosts

A large hosts file could cause a slowdown here.

[Wolfe1]

Or perhaps you are using a proxy without this checked?

[naeemakram]

WinAppDriver is innocent in this case, it is not responsible for translating the localhost.
The slowness is not the root cause, it is the symptom of some other problem with the system.
The simple solution would be to not use localhost, just go with 127.0.0.1.

[resp78]

I too have noticed that it run slow with default configuration.

[TroyWalshProf]

Did some more investigation and it appears this is a .Net core issue.

Notes*

• Only happens on Dotnet Core.
• Have reproduced this behavior with the Microsoft.AspNet.WebApi.Client
• 99% sure this is is the real issue - HttpWebRequest hits 1s timeout when resolving http://localhost on Win10 (.NET Framework is fast) dotnet/runtime#23581 (comment)