Prettify diff generated by git for encripted file:

- @sinsoku had the idea and started implementing it few months ago
  but sadly didn't finish it.
  This PR is taking over his work.

  The credentials feature has changed a lot since @sinsoku opened hi
  PR, it was easier to just restart from scratch instead of checking
  out his branch.
  Sinsoku will get all the credit he deserves for this idea :)

  TL;DR on that that feature is to make the `git diff` or `git log`
  of encrypted files to be readable.

  The previous implementation was only setting up the git required
  configuration for the first time Rails was bootstraped, so I decided
  to instead provide the user a choice to opt-in for readable diff
  credential whenever a user types the `bin/rails credentials:edit`
  command.
  The question won't be asked in the future the user has already
  answered or if the user already opted in.

  Co-authored-by: Takumi Shotoku <insoku.listy@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
index 0fe62df8ba..6077ba3ee7 100644
--- a/railties/test/isolation/abstract_unit.rb
+++ b/railties/test/isolation/abstract_unit.rb
@@ -301,7 +301,7 @@ module TestHelpers
     # stderr:: true to pass STDERR output straight to the "real" STDERR.
     #   By default, the STDERR and STDOUT of the process will be
     #   combined in the returned string.
-    def rails(*args, allow_failure: false, stderr: false)
+    def rails(*args, allow_failure: false, stderr: false, stdin: File::NULL)
       args = args.flatten
       fork = true
 
@@ -328,7 +328,7 @@ module TestHelpers
           out_read.close
           err_read.close if err_read
 
-          $stdin.reopen(File::NULL, "r")
+          $stdin.reopen(stdin, "r")
           $stdout.reopen(out_write)
           $stderr.reopen(err_write)