Remove unnecessary stuffsimplify_gems_used_by_tests_installation

Tests automatically download and install the test gems they need if not
installed, so this should be unnecessary.

However, removing it create a single spec failure only reproducible on a
fresh clone (where the path where the test gems are installed,
`tmp/gems`, has not yet been populated.

The problem was that the code branch that installs the gems uses the
`FileUtils` constant. Accessing that constant makes [this autoload]
trigger the custom rubygems `require` behavior which will end up setting
and memoizing `gem_home` to the value it has at that point (when calling
`to_spec` on the selected default gem). But at that point,
`Gem.clear_paths` call has already happened, that means `gem_home` won't
be changed during the duration of the test because it's memoized.

This situation makes a specific test that updates `ENV["HOME"]` and
expects he path to the configuration file rubygems uses to be updated fail.

This could be fixed by removing the `FileUtils` autoload, or stop
memoizing `Gem.home`, but the simplest fix seemed to require `fileutils`
early, so that `Gem.home` is not memoized again after calling
`Gem.clear_paths`.

[this autoload]: https://github.com/rubygems/rubygems/blob/511a0f5105ca95b8e389bf477b6c7cf3e90be7d1/lib/rubygems/source.rb#L3

2 files changed, 1 insertions, 5 deletions

diff --git a/Rakefile b/Rakefile
index 0a4d9c8900..105faf927d 100644
--- a/Rakefile
+++ b/Rakefile
@@ -54,11 +54,6 @@ namespace :spec do
       "'#{name}:#{version}'"
     end.join(" ")
     sh %(#{Gem.ruby} -S gem #{gem_install_command})
-
-    # Download and install gems used inside tests
-    $LOAD_PATH.unshift("./spec")
-    require "support/rubygems_ext"
-    Spec::Rubygems.setup
   end
 
   namespace :travis do
diff --git a/spec/support/rubygems_ext.rb b/spec/support/rubygems_ext.rb
index edd66278ad..2f3d252865 100644
--- a/spec/support/rubygems_ext.rb
+++ b/spec/support/rubygems_ext.rb
@@ -2,6 +2,7 @@
 
 require "rubygems/user_interaction"
 require "support/path"
+require "fileutils"
 
 module Spec
   module Rubygems