diff --git a/Library/Homebrew/cask/Gemfile b/Library/Homebrew/cask/Gemfile
index dc5c43208d..5572387ccd 100644
--- a/Library/Homebrew/cask/Gemfile
+++ b/Library/Homebrew/cask/Gemfile
@@ -1,24 +1,13 @@
 source "https://rubygems.org"
 
-gem "rake"
-
 group :test do
-  # This is SimpleCov v0.12.0 with two fixes merged on top, that finally resolve
-  # all issues with parallel tests, uncovered files, and tracked files. Switch
-  # back to stable as soon as v0.12.1 or v0.13.0 is released. For details, see:
-  #  - https://github.com/colszowka/simplecov/pull/513
-  #  - https://github.com/colszowka/simplecov/pull/520
-  gem "simplecov", "0.12.0",
-    git: "https://github.com/colszowka/simplecov.git",
-    branch: "master",
-    ref: "83d8031ddde0927f87ef9327200a98583ca18d77",
-    require: false
+  gem "simplecov", require: false
   gem "codecov", require: false
-  gem "minitest", "~> 5.9"
+  gem "minitest"
   gem "minitest-reporters"
-  gem "mocha", "~> 1.1", require: false
+  gem "mocha", require: false
   gem "parallel_tests"
-  gem "rspec", "~> 3.5"
+  gem "rspec"
   gem "rspec-its", require: false
   gem "rspec-wait", require: false
 end
diff --git a/Library/Homebrew/cask/Gemfile.lock b/Library/Homebrew/cask/Gemfile.lock
index 28c05c655e..700f093d1e 100644
--- a/Library/Homebrew/cask/Gemfile.lock
+++ b/Library/Homebrew/cask/Gemfile.lock
@@ -1,29 +1,18 @@
-GIT
-  remote: https://github.com/colszowka/simplecov.git
-  revision: 83d8031ddde0927f87ef9327200a98583ca18d77
-  ref: 83d8031ddde0927f87ef9327200a98583ca18d77
-  branch: master
-  specs:
-    simplecov (0.12.0)
-      docile (~> 1.1.0)
-      json (>= 1.8, < 3)
-      simplecov-html (~> 0.10.0)
-
 GEM
   remote: https://rubygems.org/
   specs:
     ansi (1.5.0)
-    builder (3.2.2)
+    builder (3.2.3)
     codecov (0.1.9)
       json
       simplecov
       url
-    diff-lcs (1.2.5)
+    diff-lcs (1.3)
     docile (1.1.5)
-    json (2.0.2)
+    json (2.0.3)
     metaclass (0.0.4)
     minitest (5.10.1)
-    minitest-reporters (1.1.13)
+    minitest-reporters (1.1.14)
       ansi
       builder
       minitest (>= 5.0)
@@ -31,9 +20,8 @@ GEM
     mocha (1.2.1)
       metaclass (~> 0.0.1)
     parallel (1.10.0)
-    parallel_tests (2.10.0)
+    parallel_tests (2.13.0)
       parallel
-    rake (12.0.0)
     rspec (3.5.0)
       rspec-core (~> 3.5.0)
       rspec-expectations (~> 3.5.0)
@@ -53,6 +41,10 @@ GEM
     rspec-wait (0.0.9)
       rspec (>= 3, < 4)
     ruby-progressbar (1.8.1)
+    simplecov (0.13.0)
+      docile (~> 1.1.0)
+      json (>= 1.8, < 3)
+      simplecov-html (~> 0.10.0)
     simplecov-html (0.10.0)
     url (0.3.2)
 
@@ -61,15 +53,14 @@ PLATFORMS
 
 DEPENDENCIES
   codecov
-  minitest (~> 5.9)
+  minitest
   minitest-reporters
-  mocha (~> 1.1)
+  mocha
   parallel_tests
-  rake
-  rspec (~> 3.5)
+  rspec
   rspec-its
   rspec-wait
-  simplecov (= 0.12.0)!
+  simplecov
 
 BUNDLED WITH
-   1.13.6
+   1.13.7
diff --git a/Library/Homebrew/cask/Rakefile b/Library/Homebrew/cask/Rakefile
deleted file mode 100644
index b2b9fce526..0000000000
--- a/Library/Homebrew/cask/Rakefile
+++ /dev/null
@@ -1,17 +0,0 @@
-require "rake/testtask"
-require "rspec/core/rake_task"
-
-$LOAD_PATH.unshift(File.expand_path("#{ENV["HOMEBREW_REPOSITORY"]}/Library/Homebrew"))
-$LOAD_PATH.unshift(File.expand_path("../lib", __FILE__))
-
-namespace :test do
-  namespace :coverage do
-    desc "Upload coverage to Codecov"
-    task :upload do
-      require "simplecov"
-      require "codecov"
-      formatter = SimpleCov::Formatter::Codecov.new
-      formatter.format(SimpleCov::ResultMerger.merged_result)
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/cmd/brew-cask-tests.rb b/Library/Homebrew/cask/cmd/brew-cask-tests.rb
index 43683a2634..bdcabd4dc8 100755
--- a/Library/Homebrew/cask/cmd/brew-cask-tests.rb
+++ b/Library/Homebrew/cask/cmd/brew-cask-tests.rb
@@ -10,8 +10,8 @@ def run_tests(executable, files, args = [])
   system "bundle", "exec", executable, *opts, "--", *args, "--", *files
 end
 
-repo_root = Pathname.new(__FILE__).realpath.parent.parent
-repo_root.cd do
+cask_root = Pathname.new(__FILE__).realpath.parent.parent
+cask_root.cd do
   ENV["HOMEBREW_NO_ANALYTICS_THIS_RUN"] = "1"
   ENV["HOMEBREW_NO_EMOJI"] = "1"
   ENV.delete("HOMEBREW_CASK_OPTS")
@@ -24,7 +24,6 @@ repo_root.cd do
   rspec = ARGV.flag?("--rspec") || !ARGV.flag?("--minitest")
   minitest = ARGV.flag?("--minitest") || !ARGV.flag?("--rspec")
 
-  p [:coverage, ARGV.flag?("--coverage"), ENV["CI"], ENV["TRAVIS"]]
   if ARGV.flag?("--coverage")
     ENV["HOMEBREW_TESTS_COVERAGE"] = "1"
     upload_coverage = ENV["CODECOV_TOKEN"] || ENV["TRAVIS"]
@@ -52,6 +51,6 @@ repo_root.cd do
 
   if upload_coverage
     puts "Submitting Codecov coverage..."
-    system "bundle", "exec", "rake", "test:coverage:upload"
+    system "bundle", "exec", "test/upload_coverage.rb"
   end
 end
diff --git a/Library/Homebrew/cask/test/upload_coverage.rb b/Library/Homebrew/cask/test/upload_coverage.rb
new file mode 100755
index 0000000000..06d38157dd
--- /dev/null
+++ b/Library/Homebrew/cask/test/upload_coverage.rb
@@ -0,0 +1,6 @@
+#!/usr/bin/env ruby
+require "simplecov"
+require "codecov"
+
+formatter = SimpleCov::Formatter::Codecov.new
+formatter.format SimpleCov::ResultMerger.merged_result
diff --git a/Library/Homebrew/test/Gemfile b/Library/Homebrew/test/Gemfile
index a7e9eb8344..2a66086bd6 100644
--- a/Library/Homebrew/test/Gemfile
+++ b/Library/Homebrew/test/Gemfile
@@ -1,20 +1,10 @@
 source "https://rubygems.org"
 
-gem "mocha", "~> 1.1"
-gem "minitest", "~> 5.3"
-gem "rake", "~> 10.3"
-gem "parallel_tests", "~> 2.9"
+gem "mocha"
+gem "minitest"
+gem "parallel_tests"
 
 group :coverage do
-  # This is SimpleCov v0.12.0 with two fixes merged on top, that finally resolve
-  # all issues with parallel tests, uncovered files, and tracked files. Switch
-  # back to stable as soon as v0.12.1 or v0.13.0 is released. For details, see:
-  #  - https://github.com/colszowka/simplecov/pull/513
-  #  - https://github.com/colszowka/simplecov/pull/520
-  gem "simplecov", "0.12.0",
-    git: "https://github.com/colszowka/simplecov.git",
-    branch: "master",
-    ref: "83d8031ddde0927f87ef9327200a98583ca18d77",
-    require: false
+  gem "simplecov", require: false
   gem "codecov", require: false
 end
diff --git a/Library/Homebrew/test/Gemfile.lock b/Library/Homebrew/test/Gemfile.lock
index aa4800f34f..8289fcc202 100644
--- a/Library/Homebrew/test/Gemfile.lock
+++ b/Library/Homebrew/test/Gemfile.lock
@@ -1,31 +1,23 @@
-GIT
-  remote: https://github.com/colszowka/simplecov.git
-  revision: 83d8031ddde0927f87ef9327200a98583ca18d77
-  ref: 83d8031ddde0927f87ef9327200a98583ca18d77
-  branch: master
-  specs:
-    simplecov (0.12.0)
-      docile (~> 1.1.0)
-      json (>= 1.8, < 3)
-      simplecov-html (~> 0.10.0)
-
 GEM
   remote: https://rubygems.org/
   specs:
-    codecov (0.1.6)
+    codecov (0.1.9)
       json
       simplecov
       url
     docile (1.1.5)
-    json (2.0.2)
+    json (2.0.3)
     metaclass (0.0.4)
-    minitest (5.9.1)
+    minitest (5.10.1)
     mocha (1.2.1)
       metaclass (~> 0.0.1)
-    parallel (1.9.0)
-    parallel_tests (2.10.0)
+    parallel (1.10.0)
+    parallel_tests (2.13.0)
       parallel
-    rake (10.5.0)
+    simplecov (0.13.0)
+      docile (~> 1.1.0)
+      json (>= 1.8, < 3)
+      simplecov-html (~> 0.10.0)
     simplecov-html (0.10.0)
     url (0.3.2)
 
@@ -34,11 +26,10 @@ PLATFORMS
 
 DEPENDENCIES
   codecov
-  minitest (~> 5.3)
-  mocha (~> 1.1)
-  parallel_tests (~> 2.9)
-  rake (~> 10.3)
-  simplecov (= 0.12.0)!
+  minitest
+  mocha
+  parallel_tests
+  simplecov
 
 BUNDLED WITH
-   1.13.6
+   1.13.7
diff --git a/Library/Homebrew/test/shell_test.rb b/Library/Homebrew/test/shell_test.rb
index a32d098638..a04ab83311 100644
--- a/Library/Homebrew/test/shell_test.rb
+++ b/Library/Homebrew/test/shell_test.rb
@@ -14,9 +14,9 @@ class ShellSmokeTest < Homebrew::TestCase
   end
 
   def test_path_to_shell_failure
-    assert_equal nil, Utils::Shell.path_to_shell("")
-    assert_equal nil, Utils::Shell.path_to_shell("@@@@@@")
-    assert_equal nil, Utils::Shell.path_to_shell("invalid_shell-4.2")
+    assert_nil Utils::Shell.path_to_shell("")
+    assert_nil Utils::Shell.path_to_shell("@@@@@@")
+    assert_nil Utils::Shell.path_to_shell("invalid_shell-4.2")
   end
 
   def test_sh_quote
diff --git a/Library/Homebrew/test/tab_test.rb b/Library/Homebrew/test/tab_test.rb
index f6f55348d1..b48efcf5ce 100644
--- a/Library/Homebrew/test/tab_test.rb
+++ b/Library/Homebrew/test/tab_test.rb
@@ -241,15 +241,18 @@ class TabTests < Homebrew::TestCase
     assert_equal @tab.changed_files, tab.changed_files
     assert_equal @tab.tap, tab.tap
     assert_equal @tab.spec, tab.spec
-    assert_equal @tab.time, tab.time
+    assert_nil @tab.time
+    assert_nil tab.time
     assert_equal @tab.HEAD, tab.HEAD
     assert_equal @tab.compiler, tab.compiler
     assert_equal @tab.stdlib, tab.stdlib
-    assert_equal @tab.runtime_dependencies, tab.runtime_dependencies
+    assert_nil @tab.runtime_dependencies
+    assert_nil tab.runtime_dependencies
     assert_equal @tab.stable_version, tab.stable_version
     assert_equal @tab.devel_version, tab.devel_version
     assert_equal @tab.head_version, tab.head_version
-    assert_equal @tab.source["path"], tab.source["path"]
+    assert_nil @tab.source["path"]
+    assert_nil tab.source["path"]
   end
 
   def test_remap_deprecated_options