Fixed #24364 -- Doc'ed that ManifestStaticFileStorage shouldn't be used during testing.

AUTHORS

@@ -17,6 +17,7 @@ answer newbie questions, and generally made Django that much better:
     Ahmad Al-Ibrahim
     ajs <adi@sieker.info>
     Akis Kesoglou <akiskesoglou@gmail.com>
+    Aksel Ethem <aksel.ethem@gmail.com>
     alang@bright-green.com
     Alasdair Nicol <http://al.sdair.co.uk/>
     Albert Wang <aywang31@gmail.com>

docs/ref/contrib/staticfiles.txt

@@ -285,6 +285,12 @@ hashed names for all processed files in a file called ``staticfiles.json``.
 This happens once when you run the :djadmin:`collectstatic` management
 command.
 
+Due to the requirement of running :djadmin:`collectstatic`, this storage
+typically shouldn't be used when running tests as ``collectstatic`` isn't run
+as part of the normal test setup. During testing, ensure that the
+:setting:`STATICFILES_STORAGE` setting is set to something else like
+``'django.contrib.staticfiles.storage.StaticFilesStorage'`` (the default).
+
 .. method:: storage.ManifestStaticFilesStorage.file_hash(name, content=None)
 
 The method that is used when creating the hashed name of a file.