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Is There Another Way to Do This?
All Browsers have an Advanced section of their Options where under Network you can configure desktop Browers have a configuration option to specify the network address of a Proxy Server. When we have the time, we will set up a Proxy Server and then you can test Shibboleth using a change to the Browser configuration instead of a change to the hosts file. Doing this is actually a bit more complicated, but because of the bad association of hosts file changes and malware, some people today may feel better about this change. We have not yet set up the proxy.We have also set up a Windows VM in the "SpinUp" test environment that always has the modified hosts file. If for some reason you do not want to make the hosts change on your computer, you can request that your Netid be added to the users who can login to that computer, and then you can perform the test through the Remote Desktop sessionWe could create a special Proxy Server that reroutes requests for "auth.yale.edu" to the Pre-Production machine. However, after messing with a hosts file, the second most popular malware trick is to mess with the Proxy configuration. Routing Web traffic, particularly traffic to high security applications like CAS and Shibboleth, through a Proxy machine is not a good practice and we do not want to encourage it. You are certainly free to use Proxy servers that you control in your own testing.
We have created a Windows VM and permanently set the hosts file to point to Pre-Production. If someone were unable to make changes to their own machine, we could add their Netid to the list of users who can use Remote Desktop to login to the machine and test their application using one of the Browsers. Again this does not appear to be an optimal solution, and again you are free to install a VM host on your desktop (we recommend Virtualbox from Oracle) and run test cases in a VM that you would rather not run on your regular operating system.
Generally speaking, it is not possible to change the hosts file on a normal (non "rooted") Android computer, so you cannot test from a phone or tablet computer.
Changing the hosts file is simple and easy to understand, and it is completely under your control. Many people still have some laptop they replaced 6 years ago sitting on a shelf, and it is perfectly acceptable to run the test on that machine.