Update aur dev.archlinux.org Testing

aur-dev.archlinux.org-Testing.md

@@ -1 +1,64 @@
-TBA
+## Preface
+
+Testers using the https://aur-dev.archlinux.org instance should
+read the following sections:
+
+- [Toggling Between FastAPI and PHP](#toggling-between-fastapi-and-php)
+- [Data](#data)
+- [Accounts](#accounts)
+
+## Toggling Between FastAPI and PHP
+
+https://aur-dev.archlinux.org provides a method of toggling between
+the two implementations using the `version` cookie.
+
+To toggle between FastAPI and PHP, users should utilize
+https://aur-dev.archlinux.org/version, which contains an explanation of
+using the `?version={choice}` query string parameter, where
+`{choice}` is one of `fastapi` or `php`.
+
+TL;DR: To switch to one of the following choices, browse to its endpoint:
+
+| Choice    | Endpoint                                              |
+|-----------|-------------------------------------------------------|
+| `fastapi` | https://aur-dev.archlinux.org/version?version=fastapi |
+| `php`     | https://aur-dev.archlinux.org/version?version=php     |
+
+To check which choice you're currently on, visit
+https://aur-dev.archlinux.org/version, which displays your current choice.
+
+## Data
+
+The majority of data that can be found on the aur-dev instance is
+generated dummy data, with the exception of any tester-driven packages.
+
+## Accounts
+
+#### Dummy Users
+
+Each dummy user (the majority of users) on the instance use the
+same username and password. This is not the case if an account
+request was accepted or a dummy user has had their password
+modified by another tester.
+
+#### Registration
+
+Standard account registration cannot occur on aur-dev, due to the fact
+that notifications are disabled and users do not have access to its
+database.
+
+However, if you do want your own account name or specific account type,
+you can request an account in two ways:
+
+- By filing an [Account Request](https://gitlab.archlinux.org/archlinux/aurweb/-/issues/new?issuable_template=Account%20Request) issue
+    - Title: `[Account Request] the_name_you_want`
+- By sending an email to aur-dev@lists.archlinux.org
+    - Subject: `[Account Request] the_name_you_want`
+    - Content should use the [Account Request template](https://gitlab.archlinux.org/archlinux/aurweb/-/tree/master/.gitlab/issue_templates/Account%20Request.md)
+
+Upon receiving such a request, we will then register the account, receive
+the needed reset key, and send an email to that which is specified in the
+`Email` field of the request containing your reset key and a link to
+`/passreset?resetkey={your_reset_key}`.
+
+Using this link, you can then configure your own password for the account.