diff --git a/Library/Homebrew/cask/spec/cask/cli_spec.rb b/Library/Homebrew/cask/spec/cask/cli_spec.rb
index 9964275f10..6b2313a41c 100644
--- a/Library/Homebrew/cask/spec/cask/cli_spec.rb
+++ b/Library/Homebrew/cask/spec/cask/cli_spec.rb
@@ -39,17 +39,17 @@ describe Hbc::CLI do
     end
 
     it "respects the env variable when choosing what appdir to create" do
-      with_environment "HOMEBREW_CASK_OPTS" => "--appdir=/custom/appdir" do
-        expect(Hbc).to receive(:appdir=).with(Pathname("/custom/appdir"))
-        described_class.process("noop")
-      end
+      allow(ENV).to receive(:[])
+      allow(ENV).to receive(:[]).with("HOMEBREW_CASK_OPTS").and_return("--appdir=/custom/appdir")
+      expect(Hbc).to receive(:appdir=).with(Pathname.new("/custom/appdir"))
+      described_class.process("noop")
     end
 
     it "respects the env variable when choosing a non-default Caskroom location" do
-      with_environment "HOMEBREW_CASK_OPTS" => "--caskroom=/custom/caskdir" do
-        expect(Hbc).to receive(:caskroom=).with(Pathname("/custom/caskdir"))
-        described_class.process("noop")
-      end
+      allow(ENV).to receive(:[])
+      allow(ENV).to receive(:[]).with("HOMEBREW_CASK_OPTS").and_return("--caskroom=/custom/caskdir")
+      expect(Hbc).to receive(:caskroom=).with(Pathname.new("/custom/caskdir"))
+      described_class.process("noop")
     end
 
     it "exits with a status of 1 when something goes wrong" do
diff --git a/Library/Homebrew/cask/spec/spec_helper.rb b/Library/Homebrew/cask/spec/spec_helper.rb
index 458fe00f4f..162cb3b8f3 100644
--- a/Library/Homebrew/cask/spec/spec_helper.rb
+++ b/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
diff --git a/Library/Homebrew/cask/test/cask/dsl_test.rb b/Library/Homebrew/cask/test/cask/dsl_test.rb
index 96d24a1a14..0ea928f40e 100644
--- a/Library/Homebrew/cask/test/cask/dsl_test.rb
+++ b/Library/Homebrew/cask/test/cask/dsl_test.rb
@@ -69,7 +69,11 @@ describe Hbc::DSL do
     end
 
     it "may use deprecated DSL version hash syntax" do
-      with_environment "HOMEBREW_DEVELOPER" => nil do
+      stub = proc do |arg|
+        arg == "HOMEBREW_DEVELOPER" ? nil : ENV[arg]
+      end
+
+      ENV.stub :[], stub do
         shutup do
           test_cask = Hbc.load("with-dsl-version")
           test_cask.token.must_equal "with-dsl-version"
diff --git a/Library/Homebrew/cask/test/test_helper.rb b/Library/Homebrew/cask/test/test_helper.rb
index 275ede3048..7315839f58 100644
--- a/Library/Homebrew/cask/test/test_helper.rb
+++ b/Library/Homebrew/cask/test/test_helper.rb
@@ -13,9 +13,7 @@ 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"
-include Test::Helper::Env
 include Test::Helper::Shutup
 
 def sudo(*args)
diff --git a/Library/Homebrew/dev-cmd/tests.rb b/Library/Homebrew/dev-cmd/tests.rb
index b4f3c2d40d..05bdda8d2e 100644
--- a/Library/Homebrew/dev-cmd/tests.rb
+++ b/Library/Homebrew/dev-cmd/tests.rb
@@ -34,6 +34,7 @@ module Homebrew
       %w[AUTHOR COMMITTER].each do |role|
         ENV["GIT_#{role}_NAME"] = "brew tests"
         ENV["GIT_#{role}_EMAIL"] = "brew-tests@localhost"
+        ENV["GIT_#{role}_DATE"]  = "Sun Jan 22 19:59:13 2017 +0000"
       end
 
       Homebrew.install_gem_setup_path! "bundler"
diff --git a/Library/Homebrew/test/audit_test.rb b/Library/Homebrew/test/audit_test.rb
index f8d1374822..60cf276106 100644
--- a/Library/Homebrew/test/audit_test.rb
+++ b/Library/Homebrew/test/audit_test.rb
@@ -243,7 +243,7 @@ class FormulaAuditorTests < Homebrew::TestCase
     needs_compat
     require "compat/formula_specialties"
 
-    ARGV.stubs(:homebrew_developer?).returns false
+    ENV.delete("HOMEBREW_DEVELOPER")
     fa = shutup do
       formula_auditor "foo", <<-EOS.undent
         class Foo < GithubGistFormula
@@ -260,7 +260,7 @@ class FormulaAuditorTests < Homebrew::TestCase
     needs_compat
     require "compat/formula_specialties"
 
-    ARGV.stubs(:homebrew_developer?).returns false
+    ENV.delete("HOMEBREW_DEVELOPER")
     fa = formula_auditor "foo", <<-EOS.undent
       class Foo < ScriptFileFormula
         url "http://example.com/foo-1.0.tgz"
@@ -275,7 +275,7 @@ class FormulaAuditorTests < Homebrew::TestCase
     needs_compat
     require "compat/formula_specialties"
 
-    ARGV.stubs(:homebrew_developer?).returns false
+    ENV.delete("HOMEBREW_DEVELOPER")
     fa = formula_auditor "foo", <<-EOS.undent
       class Foo < AmazonWebServicesFormula
         url "http://example.com/foo-1.0.tgz"
@@ -361,13 +361,10 @@ class FormulaAuditorTests < Homebrew::TestCase
       end
     EOS
 
-    original_value = ENV["HOMEBREW_NO_GITHUB_API"]
     ENV["HOMEBREW_NO_GITHUB_API"] = "1"
 
     fa.audit_github_repository
     assert_equal [], fa.problems
-  ensure
-    ENV["HOMEBREW_NO_GITHUB_API"] = original_value
   end
 
   def test_audit_caveats
diff --git a/Library/Homebrew/test/commands_test.rb b/Library/Homebrew/test/commands_test.rb
index 3d7c16e58f..5f5dc95865 100644
--- a/Library/Homebrew/test/commands_test.rb
+++ b/Library/Homebrew/test/commands_test.rb
@@ -47,8 +47,6 @@ class CommandsTests < Homebrew::TestCase
   end
 
   def test_external_commands
-    env = ENV.to_hash
-
     mktmpdir do |dir|
       %w[brew-t1 brew-t2.rb brew-t3.py].each do |file|
         path = "#{dir}/#{file}"
@@ -67,8 +65,6 @@ class CommandsTests < Homebrew::TestCase
         "Executable files with a non Ruby extension shoudn't be included"
       refute cmds.include?("t4"), "Non-executable files shouldn't be included"
     end
-  ensure
-    ENV.replace(env)
   end
 
   def test_internal_command_path
diff --git a/Library/Homebrew/test/diagnostic_test.rb b/Library/Homebrew/test/diagnostic_test.rb
index 2d12868273..7a1fb25f79 100644
--- a/Library/Homebrew/test/diagnostic_test.rb
+++ b/Library/Homebrew/test/diagnostic_test.rb
@@ -6,15 +6,9 @@ require "diagnostic"
 class DiagnosticChecksTest < Homebrew::TestCase
   def setup
     super
-    @env = ENV.to_hash
     @checks = Homebrew::Diagnostic::Checks.new
   end
 
-  def teardown
-    ENV.replace(@env)
-    super
-  end
-
   def test_inject_file_list
     assert_equal "foo:\n",
       @checks.inject_file_list([], "foo:\n")
diff --git a/Library/Homebrew/test/download_strategies_test.rb b/Library/Homebrew/test/download_strategies_test.rb
index 604671b1e7..40236b420a 100644
--- a/Library/Homebrew/test/download_strategies_test.rb
+++ b/Library/Homebrew/test/download_strategies_test.rb
@@ -157,28 +157,14 @@ 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
-        shutup do
-          system "git", "init"
-          system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
-        end
-        touch "README"
-        git_commit_all
+    @cached_location.cd do
+      shutup do
+        system "git", "init"
+        system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
       end
+      touch "README"
+      git_commit_all
     end
   end
 
@@ -192,18 +178,16 @@ class GitDownloadStrategyTests < Homebrew::TestCase
 
   def test_source_modified_time
     setup_git_repo
-    assert_equal 1_242_860_651, @strategy.source_modified_time.to_i
+    assert_equal 1_485_115_153, @strategy.source_modified_time.to_i
   end
 
   def test_last_commit
     setup_git_repo
-    using_git_env do
-      @cached_location.cd do
-        touch "LICENSE"
-        git_commit_all
-      end
+    @cached_location.cd do
+      touch "LICENSE"
+      git_commit_all
     end
-    assert_equal "c50c79b", @strategy.last_commit
+    assert_equal "f68266e", @strategy.last_commit
   end
 
   def test_fetch_last_commit
@@ -214,21 +198,19 @@ class GitDownloadStrategyTests < Homebrew::TestCase
     resource.instance_variable_set(:@version, Version.create("HEAD"))
     @strategy = GitDownloadStrategy.new("baz", resource)
 
-    using_git_env do
-      remote_repo.cd do
-        shutup do
-          system "git", "init"
-          system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
-        end
-        touch "README"
-        git_commit_all
-        touch "LICENSE"
-        git_commit_all
+    remote_repo.cd do
+      shutup do
+        system "git", "init"
+        system "git", "remote", "add", "origin", "https://github.com/Homebrew/homebrew-foo"
       end
+      touch "README"
+      git_commit_all
+      touch "LICENSE"
+      git_commit_all
     end
 
     @strategy.shutup!
-    assert_equal "c50c79b", @strategy.fetch_last_commit
+    assert_equal "f68266e", @strategy.fetch_last_commit
   ensure
     remote_repo.rmtree if remote_repo.directory?
   end
diff --git a/Library/Homebrew/test/formula_test.rb b/Library/Homebrew/test/formula_test.rb
index a043423114..ecdd1847b9 100644
--- a/Library/Homebrew/test/formula_test.rb
+++ b/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 +533,6 @@ 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
-
     cached_location.cd do
       FileUtils.touch "LICENSE"
       shutup do
@@ -552,8 +544,6 @@ class FormulaTests < Homebrew::TestCase
 
     f.update_head_version
     assert_equal Version.create("HEAD-5658946"), f.head.version
-  ensure
-    ENV.replace(initial_env)
   end
 
   def test_legacy_options
@@ -1098,13 +1088,12 @@ class OutdatedVersionsTests < Homebrew::TestCase
     outdated_stable_prefix = HOMEBREW_CELLAR.join("testball/1.0")
     head_prefix_a = HOMEBREW_CELLAR.join("testball/HEAD")
     head_prefix_b = HOMEBREW_CELLAR.join("testball/HEAD-aaaaaaa_1")
-    head_prefix_c = HOMEBREW_CELLAR.join("testball/HEAD-5658946")
+    head_prefix_c = HOMEBREW_CELLAR.join("testball/HEAD-18a7103")
 
     setup_tab_for_prefix(outdated_stable_prefix)
     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 +1103,6 @@ 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
-
     testball_repo.cd do
       FileUtils.touch "LICENSE"
       shutup do
@@ -1144,7 +1127,6 @@ 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
 
diff --git a/Library/Homebrew/test/gpg2_requirement_test.rb b/Library/Homebrew/test/gpg2_requirement_test.rb
index b45798b420..3297c28512 100644
--- a/Library/Homebrew/test/gpg2_requirement_test.rb
+++ b/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
diff --git a/Library/Homebrew/test/gpg_test.rb b/Library/Homebrew/test/gpg_test.rb
index d3a6372971..ea43725491 100644
--- a/Library/Homebrew/test/gpg_test.rb
+++ b/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
diff --git a/Library/Homebrew/test/install_test.rb b/Library/Homebrew/test/install_test.rb
index fa0ef5ffee..da6c1863f5 100644
--- a/Library/Homebrew/test/install_test.rb
+++ b/Library/Homebrew/test/install_test.rb
@@ -73,13 +73,6 @@ 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
 
@@ -105,14 +98,11 @@ class IntegrationCommandTestInstall < IntegrationCommandTestCase
     # Ignore dependencies, because we'll try to resolve requirements in build.rb
     # and there will be the git requirement, but we cannot instantiate git
     # formula since we only have testball1 formula.
-    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-2ccdf4f", cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
-    assert_match "testball1-HEAD-2ccdf4f already installed",
+    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-d5eb689", cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
+    assert_match "testball1-HEAD-d5eb689 already installed",
       cmd("install", "testball1", "--HEAD", "--ignore-dependencies")
-    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-2ccdf4f", cmd("unlink", "testball1")
+    assert_match "#{HOMEBREW_CELLAR}/testball1/HEAD-d5eb689", 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
diff --git a/Library/Homebrew/test/os/mac/diagnostic_test.rb b/Library/Homebrew/test/os/mac/diagnostic_test.rb
index 284d293ca9..704235b01c 100644
--- a/Library/Homebrew/test/os/mac/diagnostic_test.rb
+++ b/Library/Homebrew/test/os/mac/diagnostic_test.rb
@@ -6,15 +6,9 @@ require "diagnostic"
 class OSMacDiagnosticChecksTest < Homebrew::TestCase
   def setup
     super
-    @env = ENV.to_hash
     @checks = Homebrew::Diagnostic::Checks.new
   end
 
-  def teardown
-    ENV.replace(@env)
-    super
-  end
-
   def test_check_for_other_package_managers
     MacOS.stubs(:macports_or_fink).returns ["fink"]
     assert_match "You have MacPorts or Fink installed:",
@@ -22,7 +16,7 @@ class OSMacDiagnosticChecksTest < Homebrew::TestCase
   end
 
   def test_check_for_unsupported_macos
-    ARGV.stubs(:homebrew_developer?).returns false
+    ENV.delete("HOMEBREW_DEVELOPER")
     OS::Mac.stubs(:prerelease?).returns true
     assert_match "We do not provide support for this pre-release version.",
       @checks.check_for_unsupported_macos
diff --git a/Library/Homebrew/test/sandbox_test.rb b/Library/Homebrew/test/sandbox_test.rb
index 2e97b5d6a2..a633defce2 100644
--- a/Library/Homebrew/test/sandbox_test.rb
+++ b/Library/Homebrew/test/sandbox_test.rb
@@ -15,11 +15,11 @@ class SandboxTest < Homebrew::TestCase
     f2 = formula { url "bar-1.0" }
     f2.stubs(:tap).returns(Tap.fetch("test/tap"))
 
-    ARGV.stubs(:sandbox?).returns true
+    ENV["HOMEBREW_SANDBOX"] = "1"
     assert Sandbox.formula?(f),
       "Formulae should be sandboxed if --sandbox was passed."
 
-    ARGV.stubs(:sandbox?).returns false
+    ENV.delete("HOMEBREW_SANDBOX")
     assert Sandbox.formula?(f),
       "Formulae should be sandboxed if in a sandboxed tap."
     refute Sandbox.formula?(f2),
@@ -27,7 +27,7 @@ class SandboxTest < Homebrew::TestCase
   end
 
   def test_test?
-    ARGV.stubs(:no_sandbox?).returns false
+    ENV.delete("HOMEBREW_NO_SANDBOX")
     assert Sandbox.test?,
       "Tests should be sandboxed unless --no-sandbox was passed."
   end
@@ -47,7 +47,7 @@ class SandboxTest < Homebrew::TestCase
 
   def test_complains_on_failure
     Utils.expects(popen_read: "foo")
-    ARGV.stubs(verbose?: true)
+    ENV["HOMEBREW_VERBOSE"] = "1"
     out, _err = capture_io do
       assert_raises(ErrorDuringExecution) { @sandbox.exec "false" }
     end
@@ -61,7 +61,7 @@ class SandboxTest < Homebrew::TestCase
       bar
     EOS
     Utils.expects(popen_read: with_bogus_error)
-    ARGV.stubs(verbose?: true)
+    ENV["HOMEBREW_VERBOSE"] = "1"
     out, _err = capture_io do
       assert_raises(ErrorDuringExecution) { @sandbox.exec "false" }
     end
diff --git a/Library/Homebrew/test/shell_test.rb b/Library/Homebrew/test/shell_test.rb
index 877acb5c8b..a32d098638 100644
--- a/Library/Homebrew/test/shell_test.rb
+++ b/Library/Homebrew/test/shell_test.rb
@@ -37,7 +37,6 @@ class ShellSmokeTest < Homebrew::TestCase
   end
 
   def prepend_path_shell(shell, path, fragment)
-    original_shell = ENV["SHELL"]
     ENV["SHELL"] = shell
 
     prepend_message = Utils::Shell.prepend_path_in_shell_profile(path)
@@ -45,8 +44,6 @@ class ShellSmokeTest < Homebrew::TestCase
       prepend_message.start_with?(fragment),
       "#{shell}: expected #{prepend_message} to match #{fragment}"
     )
-
-    ENV["SHELL"] = original_shell
   end
 
   def test_prepend_path_in_shell_profile
diff --git a/Library/Homebrew/test/support/helper/env.rb b/Library/Homebrew/test/support/helper/env.rb
deleted file mode 100644
index 904a1d4c71..0000000000
--- a/Library/Homebrew/test/support/helper/env.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-module Test
-  module Helper
-    module Env
-      def with_environment(partial_env)
-        old = ENV.to_hash
-        ENV.update partial_env
-        begin
-          yield
-        ensure
-          ENV.replace old
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/test/support/helper/test_case.rb b/Library/Homebrew/test/support/helper/test_case.rb
index 53d4e70317..ab97ef7589 100644
--- a/Library/Homebrew/test/support/helper/test_case.rb
+++ b/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
@@ -16,11 +14,14 @@ module Homebrew
 
     def setup
       super
+
       @__argv = ARGV.dup
+      @__env = ENV.to_hash # dup doesn't work on ENV
     end
 
     def teardown
       ARGV.replace(@__argv)
+      ENV.replace(@__env)
 
       Tab.clear_cache
 
diff --git a/Library/Homebrew/test/tap_test.rb b/Library/Homebrew/test/tap_test.rb
index 2ab003fd27..578326cea8 100644
--- a/Library/Homebrew/test/tap_test.rb
+++ b/Library/Homebrew/test/tap_test.rb
@@ -66,13 +66,6 @@ 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
-
     @path.cd do
       shutup do
         system "git", "init"
@@ -81,8 +74,6 @@ class TapTest < Homebrew::TestCase
         system "git", "commit", "-m", "init"
       end
     end
-  ensure
-    ENV.replace(env)
   end
 
   def test_fetch
@@ -184,10 +175,10 @@ class TapTest < Homebrew::TestCase
     touch @path/"README"
     setup_git_repo
 
-    assert_equal "e1893a6bd191ba895c71b652ff8376a6114c7fa7", @tap.git_head
-    assert_equal "e189", @tap.git_short_head
-    assert_match "years ago", @tap.git_last_commit
-    assert_equal "2009-05-21", @tap.git_last_commit_date
+    assert_equal "0453e16c8e3fac73104da50927a86221ca0740c2", @tap.git_head
+    assert_equal "0453", @tap.git_short_head
+    assert_match(/\A\d+ .+ ago\Z/, @tap.git_last_commit)
+    assert_equal "2017-01-22", @tap.git_last_commit_date
   end
 
   def test_private_remote
diff --git a/Library/Homebrew/test/utils_test.rb b/Library/Homebrew/test/utils_test.rb
index 7099e332c2..520cd4fcdd 100644
--- a/Library/Homebrew/test/utils_test.rb
+++ b/Library/Homebrew/test/utils_test.rb
@@ -7,12 +7,6 @@ class UtilTests < Homebrew::TestCase
   def setup
     super
     @dir = Pathname.new(mktmpdir)
-    @env = ENV.to_hash
-  end
-
-  def teardown
-    ENV.replace @env
-    super
   end
 
   def test_ofail
@@ -213,7 +207,7 @@ class UtilTests < Homebrew::TestCase
   end
 
   def test_odeprecated
-    ARGV.stubs(:homebrew_developer?).returns false
+    ENV.delete("HOMEBREW_DEVELOPER")
     e = assert_raises(MethodDeprecatedError) do
       odeprecated("method", "replacement",
         caller: ["#{HOMEBREW_LIBRARY}/Taps/homebrew/homebrew-core/"],