tests: remove env helper

Library/Homebrew/cask/spec/spec_helper.rb

@@ -15,7 +15,6 @@ require "global"
 # add Homebrew-Cask to load path
 $LOAD_PATH.push(HOMEBREW_LIBRARY_PATH.join("cask", "lib").to_s)
 
-require "test/support/helper/env"
 require "test/support/helper/shutup"
 
 Pathname.glob(HOMEBREW_LIBRARY_PATH.join("cask", "spec", "support", "*.rb")).each(&method(:require))
@@ -38,6 +37,5 @@ end
 
 RSpec.configure do |config|
   config.order = :random
-  config.include(Test::Helper::Env)
   config.include(Test::Helper::Shutup)
 end

Library/Homebrew/test/gpg2_requirement_test.rb

@@ -19,8 +19,7 @@ class GPG2RequirementTests < Homebrew::TestCase
   end
 
   def test_satisfied
-    with_environment("PATH" => @dir/"bin") do
-      assert_predicate GPG2Requirement.new, :satisfied?
-    end
+    ENV["PATH"] = @dir/"bin"
+    assert_predicate GPG2Requirement.new, :satisfied?
   end
 end

Library/Homebrew/test/gpg_test.rb

@@ -10,10 +10,9 @@ class GpgTest < Homebrew::TestCase
 
   def test_create_test_key
     Dir.chdir(@dir) do
-      with_environment("HOME" => @dir) do
-        shutup { Gpg.create_test_key(@dir) }
-        assert_predicate @dir/".gnupg/secring.gpg", :exist?
-      end
+      ENV["HOME"] = @dir
+      shutup { Gpg.create_test_key(@dir) }
+      assert_predicate @dir/".gnupg/secring.gpg", :exist?
     end
   end
 end

Library/Homebrew/test/support/helper/env.rb

@@ -1,21 +0,0 @@
-module Test
-  module Helper
-    module Env
-      def copy_env
-        ENV.to_hash
-      end
-
-      def restore_env(env)
-        ENV.replace(env)
-      end
-
-      def with_environment(partial_env)
-        old = copy_env
-        ENV.update partial_env
-        yield
-      ensure
-        restore_env old
-      end
-    end
-  end
-end

Library/Homebrew/test/support/helper/test_case.rb

@@ -1,11 +1,9 @@
 module Homebrew
   class TestCase < ::Minitest::Test
-    require "test/support/helper/env"
     require "test/support/helper/fs_leak_logger"
     require "test/support/helper/lifecycle_enforcer"
     require "test/support/helper/shutup"
     require "test/support/helper/version_assertions"
-    include Test::Helper::Env
     include Test::Helper::FSLeakLogger
     include Test::Helper::LifecycleEnforcer
     include Test::Helper::Shutup
@@ -18,12 +16,12 @@ module Homebrew
       super
 
       @__argv = ARGV.dup
-      @__env = copy_env
+      @__env = ENV.to_hash # dup doesn't work on ENV
     end
 
     def teardown
       ARGV.replace(@__argv)
-      restore_env @__env
+      ENV.replace(@__env)
 
       Tab.clear_cache