Mention --fast, and document running Windows tests locally

.appveyor.yml

@@ -19,6 +19,9 @@ init:
   # Stop git from changing newlines
   - git config --global core.autocrlf input
 
+# NOTE: If you change the Vim or Vader versions here, please also update the
+# instructions for running tests on Windows in ale-development.txt
+
 install:
   # Download and unpack Vim
   - ps: >-

doc/ale-development.txt

@@ -13,6 +13,7 @@ CONTENTS                                             *ale-development-contents*
   4. Testing ALE..........................|ale-development-tests|
     4.1. Writing Linter Tests.............|ale-development-linter-tests|
     4.2. Writing Fixer Tests..............|ale-development-fixer-tests|
+    4.3. Running Tests in a Windows VM....|ale-development-windows-tests|
 
 ===============================================================================
 1. Introduction                                  *ale-development-introduction*
@@ -170,6 +171,11 @@ will run all of the tests in Vader, Vint checks, and several Bash scripts for
 finding extra issues. Run `./run-tests --help` to see all of the options the
 script supports. Note that the script supports selecting particular test files.
 
+Once you get used to dealing with Vim and NeoVim compatibility issues, you
+probably want to use `./run-tests --fast -q` for running tests with only the
+fastest available Vim version, and with success messages from tests
+suppressed.
+
 Generally write tests for any changes you make. The following types of tests
 are recommended for the following types of code.
 
@@ -353,5 +359,81 @@ given the above setup are as follows.
 `AssertFixerNotExecuted`           - Check that fixers will not be executed.
 
 
+===============================================================================
+4.3 Running Tests in a Windows VM               *ale-development-windows-tests*
+
+Tests are run for ALE in a build of Vim 8 for Windows via AppVeyor. These
+tests can frequently break due to minor differences in paths and how escaping
+is done for commands on Windows. If you are a Linux or Mac user, running these
+tests locally can be difficult. Here is a process that will make that easier.
+
+First, you want to install a Windows image with VirtualBox. Install VirtualBox
+and grab a VirtualBox image for Windows such as from here:
+https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/
+
+NOTE: If you need to enter a password for the virtual machine at any point,
+the password is "Passw0rd!" without the double quotes.
+
+NOTE: If your trial period for Windows runs out, run the commands like the
+wallpaper tells you to.
+
+Your virtual machine will need to have PowerShell installed. Before you go any
+further, confirm that PowerShell is installed in your Windows virtual machine.
+
+Consult the VirtualBox documentation on how to install "Guest Additions."
+You probably want to install "Guest Additions" for most things to work
+properly.
+
+After you've loaded your virtual machine image, go into "Settings" for your
+virtual machine, and "Shared Folders." Add a shared folder with the name
+"ale", and set the "Folder Path" to the path to your ALE repository, for
+example: "/home/w0rp/ale"
+
+Find out which drive letter "ale" has been mounted as in Windows. We'll use
+"E:" as the drive letter, for example. Open the command prompt as an
+administrator by typing in `cmd` in the start menu, right clicking on the
+command prompt application, and clicking "Run as administrator." Click "Yes"
+when prompted to ask if you're sure you want to run the command prompt. You
+should type in the following command to mount the "ale" directory for testing,
+where "E:" is replaced with your drive letter. >
+
+  mklink /D C:\testplugin E:
+<
+Close the administrator Command Prompt, and try running the command
+`type C:\testplugin\LICENSE` in a new Command Prompt which you are NOT running
+as administrator. You should see the license for ALE in your terminal. After
+you have confirmed that you have mounted ALE on your machine, search in the
+Start Menu for "power shell," run PowerShell as an administrator, and issue
+the following commands to install the correct Vim and Vader versions for
+running tests. >
+
+  Add-Type -A System.IO.Compression.FileSystem
+
+  Invoke-WebRequest ftp://ftp.vim.org/pub/vim/pc/vim80-586w32.zip -OutFile C:\vim.zip
+  [IO.Compression.ZipFile]::ExtractToDirectory('C:\vim.zip', 'C:\vim')
+  rm C:\vim.zip
+
+  Invoke-WebRequest ftp://ftp.vim.org/pub/vim/pc/vim80-586rt.zip -OutFile C:\rt.zip
+  [IO.Compression.ZipFile]::ExtractToDirectory('C:\rt.zip', 'C:\vim')
+  rm C:\rt.zip
+
+  Invoke-WebRequest https://github.com/junegunn/vader.vim/archive/c6243dd81c98350df4dec608fa972df98fa2a3af.zip -OutFile C:\vader.zip
+  [IO.Compression.ZipFile]::ExtractToDirectory('C:\vader.zip', 'C:\')
+  mv C:\vader.vim-c6243dd81c98350df4dec608fa972df98fa2a3af C:\vader
+  rm C:\vader.zip
+<
+After you have finished installing everything, you can run all of the tests
+in Windows by opening a Command Prompt NOT as an administrator by navigating
+to the directory where you've mounted the ALE code, which must be named
+`C:\testplugin`, and by running the `run-tests.bat` batch file. >
+
+  cd C:\testplugin
+  run-tests
+<
+It will probably take several minutes for all of the tests to run. Be patient.
+You can run a specific test by passing the filename as an argument to the
+batch file, for example: `run-tests test/test_c_flag_parsing.vader` . This will
+give you results much more quickly.
+
 ===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl: