diff --git a/.gitignore b/.gitignore
index 2faf5af4..01ec336b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,10 +3,8 @@ sites/*/*settings*.php
 sites/example.sites.php
 
 # Ignore paths that contain generated content.
-files/
 sites/*/files
-sites/*/private
-sites/*/translations
+
 
 # Ignore default text files
 
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/html-1.txt b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/html-1.txt
new file mode 100644
index 00000000..494470d1
--- /dev/null
+++ b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/html-1.txt
@@ -0,0 +1 @@
+<h1>SimpleTest HTML</h1>
\ No newline at end of file
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-1.png b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-1.png
new file mode 100644
index 00000000..09e64d6e
Binary files /dev/null and b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-1.png differ
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-2.jpg b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-2.jpg
new file mode 100644
index 00000000..ace07d07
Binary files /dev/null and b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-2.jpg differ
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.gif b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.gif
new file mode 100644
index 00000000..432990b8
Binary files /dev/null and b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.gif differ
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.jpg b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.jpg
new file mode 100644
index 00000000..de4eace0
Binary files /dev/null and b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.jpg differ
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.png b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.png
new file mode 100644
index 00000000..39c04192
Binary files /dev/null and b/core/modules/migrate_drupal_ui/src/Tests/d6/files/core/modules/simpletest/files/image-test.png differ
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d6/files/tmp/some-temp-file.jpg b/core/modules/migrate_drupal_ui/src/Tests/d6/files/tmp/some-temp-file.jpg
new file mode 100644
index 00000000..494470d1
--- /dev/null
+++ b/core/modules/migrate_drupal_ui/src/Tests/d6/files/tmp/some-temp-file.jpg
@@ -0,0 +1 @@
+<h1>SimpleTest HTML</h1>
\ No newline at end of file
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/cube.jpeg b/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/cube.jpeg
new file mode 100644
index 00000000..652a7db7
--- /dev/null
+++ b/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/cube.jpeg
@@ -0,0 +1 @@
+********************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
\ No newline at end of file
diff --git a/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/ds9.txt b/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/ds9.txt
new file mode 100644
index 00000000..b49b7f69
--- /dev/null
+++ b/core/modules/migrate_drupal_ui/src/Tests/d7/files/sites/default/files/ds9.txt
@@ -0,0 +1,79 @@
+                __                ___               ___
+              ,' ,'              |   |              `. `.
+            ,' ,'                |===|                `. `.
+           / //                  |___|                  \\ \
+          / //                   |___|                   \\ \
+         ////                    |___|                    \\\\
+        /  /                    ||   ||                    \  \
+       /  /                     ||   ||                     \  \
+      /| |                      ||   ||                      | |\
+      || |                     | : o : |                     | ||
+     |  \|                     | .===. |                     |/  |
+     |  |\                    /| (___) |\                    /|  |
+    |__||.\         .-.      // /,_._,\ \\      .-.         /.||__|
+    |__||_.\        `-.\    //_ [:(|):] _\\    /.-'        /._||__|
+ __/|  ||___`._____ ___\\__/___/_ ||| _\___\__//___ _____.'___||_ |\__
+/___//__________/.-/_____________|.-.|_____________\-.\__________\\___\
+\___\\__\\\_____\`-\__\\\\__\____|_-_|____/_//_____/-'/__//______//__//
+   \|__||__..'         //  \ _ \__|||__/ _ /  \\         `..__||__|/
+    |__||_./        .-'/    \\   |(|)|   //    \`-.        \..||__|
+    |  || /         `-'      \\   \'/   //      `-'         \ ||  |
+     |  |/                    \| :(-): |/                    \|  |
+     |  /|                     | : o : |                     |\  |
+      || |                     | |___| |                     | ||
+      \| |                      ||   ||                      | |/
+       \  \                     ||   ||                     /  /
+        \  \                    ||___||                    /  /
+         \\\\                    |___|                    ////
+          \ \\                   |___|                   // /
+           \ \\                  |   |                  // /
+            `. `.                |===|                ,' ,'
+              `._`.              |___|              ,'_,'
+
+
+                                _     _
+                       _____---' \_n_/ `---_____
+                  _   /  ...  -----------  ...  \   _
+                 ( )-' .  '::.\__  V  __/.::'  . `-( )
+             _  .-'  ':::.  ____ \   / ____  .:::'  `-.  _
+          ,-'.`'      __.--'    \ | | /    `--.__      `'.`-.
+         / ''::..     \          || ||          /     ..::'' \
+        /  .....  ,'\,'          ||_||          `./`.  .....  \
+       / :::::' ,'               |   |               `. '::::: \
+       | '::: ,'                 |   |                 `. :::' |
+      _/  :: /                   |___|                   \ ::  \_
+     (/     /                 ,-'     `-.                 \     \)
+    _/      `.             ,-' ooo    oo `-.             ,'      \_
+   |      /`./          ,-'\               /`-.          \.'\      |
+  |  .:  /             /  \ \_ __.---.__ _/ /  \             \  :.  |
+ .' :;: |           _ / o  \[ '  \   /  ` ]/    \ _           | ::: `.
+ | ':: |           ( `-.   /      | |      \   ,-' )           | ::' |
+ |: ': |            `-./  /       ___       \  \,-'            | :' :|
+.':: ' |           |     / `-. .-' . `-. .-' \   o |           | ' ::`.
+| ::. |           | o  ,| `-. / \`_|_'/ \ .-' |.  o |           | .:: |
+ \    |_          |____|     | ` /   \ ' |     |____|          _|    /
+ (|    _]         ]____[     |- ( (O) ) -|     ]____[         [_    |)
+ /.:  |           |    |     | . \_ _/ . |     |    |           |  :.\
+| :'  |           | o  `|-,-' \ /..|..\ / `-.-|'  o |           |. ': |
+`.  :: |           | o   \ .-' `-.___.-' `-. /   o |           | ::  .'
+ | .:: |          _.\     \|      | |      \/     /._          | ::. |
+ |  ': |      _.-'   \ o   \      | |      /   o /   `-._      | :'  |
+ `.  __ |__.-'_     _.\    /[_.__ | | __._]\  o /._     _`-.__| __  .'
+  | \  \_.--''.' .-'   \  / /    `---'    \ \  /   `-. `.``--__/  / |
+   |_\ __   ,',-'       `-./  o            \,-'       `-.`.   __ /_|
+     \\ / .','             `-. oo .-. oo ,-'             `.`. \ //
+     (\\  \ \                 `-._| |_,-'                 / /  //)
+       \\  ) \                    (_)                    / (  //
+       / \/   `.                                       ,'   \/ \
+       \  .::. `.                                     ,' .:::  /
+        \  ':::. `-./`.                         .'\.-' '''''' /
+         \    '''     /_           _           _\    ::..    /
+          `-.'::'       `--.______| |______.--'           ,-'
+             `-'`-._   ..                   .: .:   _,-'`'
+                  (_)-. ::. ''::::     ::::::  : ,-(_)
+                      \_____   '' _ _    ' _____/
+                            ---._/ u \_.---
+
+Used with permission from:
+Orbital Space Station (Terok Nor - Deep Space 9) - Joe Reiss
+https://startrekasciiart.blogspot.co.uk/2011/05/deep-space-nine.html
diff --git a/core/modules/simpletest/files/README.txt b/core/modules/simpletest/files/README.txt
new file mode 100644
index 00000000..d668f6d7
--- /dev/null
+++ b/core/modules/simpletest/files/README.txt
@@ -0,0 +1,5 @@
+
+These files are useful in tests that upload files or otherwise need to
+manipulate files, in which case they are copied to the files directory as
+specified in the site settings. Dummy files can also be generated by tests in
+order to save space.
diff --git a/core/modules/simpletest/files/html-1.txt b/core/modules/simpletest/files/html-1.txt
new file mode 100644
index 00000000..494470d1
--- /dev/null
+++ b/core/modules/simpletest/files/html-1.txt
@@ -0,0 +1 @@
+<h1>SimpleTest HTML</h1>
\ No newline at end of file
diff --git a/core/modules/simpletest/files/html-2.html b/core/modules/simpletest/files/html-2.html
new file mode 100644
index 00000000..494470d1
--- /dev/null
+++ b/core/modules/simpletest/files/html-2.html
@@ -0,0 +1 @@
+<h1>SimpleTest HTML</h1>
\ No newline at end of file
diff --git a/core/modules/simpletest/files/image-1.png b/core/modules/simpletest/files/image-1.png
new file mode 100644
index 00000000..09e64d6e
Binary files /dev/null and b/core/modules/simpletest/files/image-1.png differ
diff --git a/core/modules/simpletest/files/image-2.jpg b/core/modules/simpletest/files/image-2.jpg
new file mode 100644
index 00000000..ace07d07
Binary files /dev/null and b/core/modules/simpletest/files/image-2.jpg differ
diff --git a/core/modules/simpletest/files/image-test-no-transparency.gif b/core/modules/simpletest/files/image-test-no-transparency.gif
new file mode 100644
index 00000000..15ae7772
Binary files /dev/null and b/core/modules/simpletest/files/image-test-no-transparency.gif differ
diff --git a/core/modules/simpletest/files/image-test-transparent-indexed.gif b/core/modules/simpletest/files/image-test-transparent-indexed.gif
new file mode 100644
index 00000000..eb81f591
Binary files /dev/null and b/core/modules/simpletest/files/image-test-transparent-indexed.gif differ
diff --git a/core/modules/simpletest/files/image-test-transparent-out-of-range.gif b/core/modules/simpletest/files/image-test-transparent-out-of-range.gif
new file mode 100644
index 00000000..a54df7a9
Binary files /dev/null and b/core/modules/simpletest/files/image-test-transparent-out-of-range.gif differ
diff --git a/core/modules/simpletest/files/image-test.gif b/core/modules/simpletest/files/image-test.gif
new file mode 100644
index 00000000..432990b8
Binary files /dev/null and b/core/modules/simpletest/files/image-test.gif differ
diff --git a/core/modules/simpletest/files/image-test.jpg b/core/modules/simpletest/files/image-test.jpg
new file mode 100644
index 00000000..de4eace0
Binary files /dev/null and b/core/modules/simpletest/files/image-test.jpg differ
diff --git a/core/modules/simpletest/files/image-test.png b/core/modules/simpletest/files/image-test.png
new file mode 100644
index 00000000..39c04192
Binary files /dev/null and b/core/modules/simpletest/files/image-test.png differ
diff --git a/core/modules/simpletest/files/javascript-1.txt b/core/modules/simpletest/files/javascript-1.txt
new file mode 100644
index 00000000..efd44fd9
--- /dev/null
+++ b/core/modules/simpletest/files/javascript-1.txt
@@ -0,0 +1,3 @@
+<script>
+alert('SimpleTest PHP was executed!');
+</script>
diff --git a/core/modules/simpletest/files/javascript-2.script b/core/modules/simpletest/files/javascript-2.script
new file mode 100644
index 00000000..e0206ba8
--- /dev/null
+++ b/core/modules/simpletest/files/javascript-2.script
@@ -0,0 +1,3 @@
+<script>
+alert('SimpleTest PHP was executed!');
+</script>
\ No newline at end of file
diff --git a/core/modules/simpletest/files/php-1.txt b/core/modules/simpletest/files/php-1.txt
new file mode 100644
index 00000000..c641a696
--- /dev/null
+++ b/core/modules/simpletest/files/php-1.txt
@@ -0,0 +1,4 @@
+<?php
+// @codingStandardsIgnoreFile
+print 'SimpleTest PHP was executed!';
+?>
diff --git a/core/modules/simpletest/files/php-2.php b/core/modules/simpletest/files/php-2.php
new file mode 100644
index 00000000..29738aab
--- /dev/null
+++ b/core/modules/simpletest/files/php-2.php
@@ -0,0 +1,3 @@
+<?php
+// @codingStandardsIgnoreFile
+print 'SimpleTest PHP was executed!';
diff --git a/core/modules/simpletest/files/sql-1.txt b/core/modules/simpletest/files/sql-1.txt
new file mode 100644
index 00000000..22017e97
--- /dev/null
+++ b/core/modules/simpletest/files/sql-1.txt
@@ -0,0 +1 @@
+SELECT invalid_field FROM {invalid_table}
\ No newline at end of file
diff --git a/core/modules/simpletest/files/translations/drupal-8.0.0-beta2.hu.po b/core/modules/simpletest/files/translations/drupal-8.0.0-beta2.hu.po
new file mode 100644
index 00000000..e69de29b
diff --git a/core/modules/simpletest/files/translations/drupal-8.0.0.de.po b/core/modules/simpletest/files/translations/drupal-8.0.0.de.po
new file mode 100644
index 00000000..e69de29b