tests: extract a common using_git_env method

Library/Homebrew/test/download_strategies_test.rb

@@ -157,18 +157,6 @@ class GitDownloadStrategyTests < Homebrew::TestCase
     end
   end
 
-  def using_git_env
-    initial_env = ENV.to_hash
-    %w[AUTHOR COMMITTER].each do |role|
-      ENV["GIT_#{role}_NAME"] = "brew tests"
-      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
-      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
-    end
-    yield
-  ensure
-    ENV.replace(initial_env)
-  end
-
   def setup_git_repo
     using_git_env do
       @cached_location.cd do

Library/Homebrew/test/formula_test.rb

@@ -526,8 +526,6 @@ class FormulaTests < Homebrew::TestCase
   end
 
   def test_update_head_version
-    initial_env = ENV.to_hash
-
     f = formula do
       head "foo", using: :git
     end
@@ -535,12 +533,7 @@ class FormulaTests < Homebrew::TestCase
     cached_location = f.head.downloader.cached_location
     cached_location.mkpath
 
-    %w[AUTHOR COMMITTER].each do |role|
-      ENV["GIT_#{role}_NAME"] = "brew tests"
-      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
-      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
-    end
-
+    using_git_env do
       cached_location.cd do
         FileUtils.touch "LICENSE"
         shutup do
@@ -549,11 +542,10 @@ class FormulaTests < Homebrew::TestCase
           system "git", "commit", "-m", "Initial commit"
         end
       end
+    end
 
     f.update_head_version
     assert_equal Version.create("HEAD-5658946"), f.head.version
-  ensure
-    ENV.replace(initial_env)
   end
 
   def test_legacy_options
@@ -1104,7 +1096,6 @@ class OutdatedVersionsTests < Homebrew::TestCase
     tab_a = setup_tab_for_prefix(head_prefix_a, versions: { "stable" => "1.0" })
     setup_tab_for_prefix(head_prefix_b)
 
-    initial_env = ENV.to_hash
     testball_repo = HOMEBREW_PREFIX.join("testball_repo")
     testball_repo.mkdir
 
@@ -1114,12 +1105,7 @@ class OutdatedVersionsTests < Homebrew::TestCase
       head "file://#{testball_repo}", using: :git
     end
 
-    %w[AUTHOR COMMITTER].each do |role|
-      ENV["GIT_#{role}_NAME"] = "brew tests"
-      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
-      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
-    end
-
+    using_git_env do
       testball_repo.cd do
         FileUtils.touch "LICENSE"
         shutup do
@@ -1128,6 +1114,7 @@ class OutdatedVersionsTests < Homebrew::TestCase
           system "git", "commit", "-m", "Initial commit"
         end
       end
+    end
 
     refute_predicate f.outdated_kegs(fetch_head: true), :empty?
 
@@ -1144,7 +1131,6 @@ class OutdatedVersionsTests < Homebrew::TestCase
     reset_outdated_kegs
     assert_predicate f.outdated_kegs(fetch_head: true), :empty?
   ensure
-    ENV.replace(initial_env)
     testball_repo.rmtree if testball_repo.exist?
   end
 

Library/Homebrew/test/install_test.rb

@@ -73,16 +73,10 @@ class IntegrationCommandTestInstall < IntegrationCommandTestCase
   end
 
   def test_install_head_installed
-    initial_env = ENV.to_hash
-    %w[AUTHOR COMMITTER].each do |role|
-      ENV["GIT_#{role}_NAME"] = "brew tests"
-      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
-      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
-    end
-
     repo_path = HOMEBREW_CACHE.join("repo")
     repo_path.join("bin").mkpath
 
+    using_git_env do
       repo_path.cd do
         shutup do
           system "git", "init"
@@ -93,6 +87,7 @@ class IntegrationCommandTestInstall < IntegrationCommandTestCase
           system "git", "commit", "-m", "Initial repo commit"
         end
       end
+    end
 
     setup_test_formula "testball1", <<-EOS.undent
       version "1.0"
@@ -110,9 +105,6 @@ class IntegrationCommandTestInstall < IntegrationCommandTestCase
       cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
     assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-2ccdf4f", cmd("unlink", "testball1")
     assert_match "#{HOMEBREW_CELLAR}/testball1/1.0", cmd("install", "testball1")
-
-  ensure
-    ENV.replace(initial_env)
   end
 
   def test_install_with_invalid_option

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

@@ -1,14 +1,32 @@
 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 = ENV.to_hash
+        old = copy_env
         ENV.update partial_env
-        begin
         yield
       ensure
-          ENV.replace old
-        end
+        restore_env old
+      end
+
+      def using_git_env
+        initial_env = copy_env
+        %w[AUTHOR COMMITTER].each do |role|
+          ENV["GIT_#{role}_NAME"] = "brew tests"
+          ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
+          ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
+        end
+        yield
+      ensure
+        restore_env initial_env
       end
     end
   end

Library/Homebrew/test/tap_test.rb

@@ -66,13 +66,7 @@ class TapTest < Homebrew::TestCase
   end
 
   def setup_git_repo
-    env = ENV.to_hash
-    %w[AUTHOR COMMITTER].each do |role|
-      ENV["GIT_#{role}_NAME"] = "brew tests"
-      ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
-      ENV["GIT_#{role}_DATE"] = "Thu May 21 00:04:11 2009 +0100"
-    end
-
+    using_git_env do
       @path.cd do
         shutup do
           system "git", "init"
@@ -81,8 +75,7 @@ class TapTest < Homebrew::TestCase
           system "git", "commit", "-m", "init"
         end
       end
-  ensure
-    ENV.replace(env)
+    end
   end
 
   def test_fetch