grab executable from rubygems

As done here d7fc97d3f9

actionmailer/Rakefile

@@ -14,9 +14,8 @@ Rake::TestTask.new { |t|
 
 namespace :test do
   task :isolated do
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     Dir.glob("test/**/*_test.rb").all? do |file|
-      sh(ruby, '-w', '-Ilib:test', file)
+      sh(Gem.ruby, '-w', '-Ilib:test', file)
     end or raise "Failures"
   end
 end

actionpack/Rakefile

@@ -20,9 +20,8 @@ end
 
 namespace :test do
   task :isolated do
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     test_files.all? do |file|
-      sh(ruby, '-w', '-Ilib:test', file)
+      sh(Gem.ruby, '-w', '-Ilib:test', file)
     end or raise "Failures"
   end
 end

actionview/Rakefile

@@ -18,9 +18,8 @@ end
 
 namespace :test do
   task :isolated do
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     Dir.glob("test/{active_record,template}/**/*_test.rb").all? do |file|
-      sh(ruby, '-w', '-Ilib:test', file)
+      sh(Gem.ruby, '-w', '-Ilib:test', file)
     end or raise "Failures"
   end
 

activemodel/Rakefile

@@ -13,9 +13,8 @@ end
 
 namespace :test do
   task :isolated do
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     Dir.glob("#{dir}/test/**/*_test.rb").all? do |file|
-      sh(ruby, '-w', "-I#{dir}/lib", "-I#{dir}/test", file)
+      sh(Gem.ruby, '-w', "-I#{dir}/lib", "-I#{dir}/test", file)
     end or raise "Failures"
   end
 end

activerecord/Rakefile

@@ -58,11 +58,10 @@ end
   task "isolated_test_#{adapter}" do
     adapter_short = adapter == 'db2' ? adapter : adapter[/^[a-z0-9]+/]
     puts [adapter, adapter_short].inspect
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     (Dir["test/cases/**/*_test.rb"].reject {
       |x| x =~ /\/adapters\//
     } + Dir["test/cases/adapters/#{adapter_short}/**/*_test.rb"]).all? do |file|
-      sh(ruby, '-w' ,"-Itest", file)
+      sh(Gem.ruby, '-w' ,"-Itest", file)
     end or raise "Failures"
   end
 

activesupport/Rakefile

@@ -12,9 +12,8 @@ end
 
 namespace :test do
   task :isolated do
-    ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
     Dir.glob("test/**/*_test.rb").all? do |file|
-      sh(ruby, '-w', '-Ilib:test', file)
+      sh(Gem.ruby, '-w', '-Ilib:test', file)
     end or raise "Failures"
   end
 end