diff --git a/Library/Homebrew/test/cmd/commands_spec.rb b/Library/Homebrew/test/cmd/commands_spec.rb
index f42072956b..32d07a0bc0 100644
--- a/Library/Homebrew/test/cmd/commands_spec.rb
+++ b/Library/Homebrew/test/cmd/commands_spec.rb
@@ -1,3 +1,7 @@
+require "cmd/command"
+require "cmd/commands"
+require "fileutils"
+
 describe "brew commands", :integration_test do
   it "prints a list of all available commands" do
     expect { brew "commands" }
@@ -5,3 +9,84 @@ describe "brew commands", :integration_test do
       .and be_a_success
   end
 end
+
+RSpec.shared_context "custom internal commands" do
+  let(:cmds) do
+    [
+      # internal commands
+      HOMEBREW_LIBRARY_PATH/"cmd/rbcmd.rb",
+      HOMEBREW_LIBRARY_PATH/"cmd/shcmd.sh",
+
+      # internal developer-commands
+      HOMEBREW_LIBRARY_PATH/"dev-cmd/rbdevcmd.rb",
+      HOMEBREW_LIBRARY_PATH/"dev-cmd/shdevcmd.sh",
+    ]
+  end
+
+  around(:each) do |example|
+    begin
+      cmds.each do |f|
+        FileUtils.touch f
+      end
+
+      example.run
+    ensure
+      FileUtils.rm_f cmds
+    end
+  end
+end
+
+describe Homebrew do
+  include_context "custom internal commands"
+
+  specify "::internal_commands" do
+    cmds = described_class.internal_commands
+    expect(cmds).to include("rbcmd"), "Ruby commands files should be recognized"
+    expect(cmds).to include("shcmd"), "Shell commands files should be recognized"
+    expect(cmds).not_to include("rbdevcmd"), "Dev commands shouldn't be included"
+  end
+
+  specify "::internal_developer_commands" do
+    cmds = described_class.internal_developer_commands
+    expect(cmds).to include("rbdevcmd"), "Ruby commands files should be recognized"
+    expect(cmds).to include("shdevcmd"), "Shell commands files should be recognized"
+    expect(cmds).not_to include("rbcmd"), "Non-dev commands shouldn't be included"
+  end
+
+  specify "::external_commands" do
+    Dir.mktmpdir do |dir|
+      %w[brew-t1 brew-t2.rb brew-t3.py].each do |file|
+        path = "#{dir}/#{file}"
+        FileUtils.touch path
+        FileUtils.chmod 0755, path
+      end
+
+      FileUtils.touch "#{dir}/brew-t4"
+
+      ENV["PATH"] += "#{File::PATH_SEPARATOR}#{dir}"
+      cmds = described_class.external_commands
+
+      expect(cmds).to include("t1"), "Executable files should be included"
+      expect(cmds).to include("t2"), "Executable Ruby files should be included"
+      expect(cmds).not_to include("t3"), "Executable files with a non Ruby extension shoudn't be included"
+      expect(cmds).not_to include("t4"), "Non-executable files shouldn't be included"
+    end
+  end
+end
+
+describe Commands do
+  include_context "custom internal commands"
+
+  describe "::path" do
+    specify "returns the path for an internal command" do
+      expect(described_class.path("rbcmd")).to eq(HOMEBREW_LIBRARY_PATH/"cmd/rbcmd.rb")
+      expect(described_class.path("shcmd")).to eq(HOMEBREW_LIBRARY_PATH/"cmd/shcmd.sh")
+      expect(described_class.path("idontexist1234")).to be nil
+    end
+
+    specify "returns the path for an internal developer-command" do
+      expect(described_class.path("rbdevcmd")).to eq(HOMEBREW_LIBRARY_PATH/"dev-cmd/rbdevcmd.rb")
+      expect(described_class.path("shdevcmd")).to eq(HOMEBREW_LIBRARY_PATH/"dev-cmd/shdevcmd.sh")
+    end
+  end
+end
diff --git a/Library/Homebrew/test/commands_test.rb b/Library/Homebrew/test/commands_test.rb
deleted file mode 100644
index da88ee2d51..0000000000
--- a/Library/Homebrew/test/commands_test.rb
+++ /dev/null
@@ -1,77 +0,0 @@
-require "testing_env"
-require "cmd/command"
-require "cmd/commands"
-require "fileutils"
-require "testing_env"
-
-class CommandsTests < Homebrew::TestCase
-  def setup
-    super
-    @cmds = [
-      # internal commands
-      HOMEBREW_LIBRARY_PATH/"cmd/rbcmd.rb",
-      HOMEBREW_LIBRARY_PATH/"cmd/shcmd.sh",
-
-      # internal development commands
-      HOMEBREW_LIBRARY_PATH/"dev-cmd/rbdevcmd.rb",
-      HOMEBREW_LIBRARY_PATH/"dev-cmd/shdevcmd.sh",
-    ]
-
-    @cmds.each { |f| FileUtils.touch f }
-  end
-
-  def teardown
-    @cmds.each(&:unlink)
-    super
-  end
-
-  def test_internal_commands
-    cmds = Homebrew.internal_commands
-    assert cmds.include?("rbcmd"), "Ruby commands files should be recognized"
-    assert cmds.include?("shcmd"), "Shell commands files should be recognized"
-    refute cmds.include?("rbdevcmd"), "Dev commands shouldn't be included"
-  end
-
-  def test_internal_developer_commands
-    cmds = Homebrew.internal_developer_commands
-    assert cmds.include?("rbdevcmd"), "Ruby commands files should be recognized"
-    assert cmds.include?("shdevcmd"), "Shell commands files should be recognized"
-    refute cmds.include?("rbcmd"), "Non-dev commands shouldn't be included"
-  end
-
-  def test_external_commands
-    mktmpdir do |dir|
-      %w[brew-t1 brew-t2.rb brew-t3.py].each do |file|
-        path = "#{dir}/#{file}"
-        FileUtils.touch path
-        FileUtils.chmod 0755, path
-      end
-
-      FileUtils.touch "#{dir}/brew-t4"
-
-      ENV["PATH"] += "#{File::PATH_SEPARATOR}#{dir}"
-      cmds = Homebrew.external_commands
-
-      assert cmds.include?("t1"), "Executable files should be included"
-      assert cmds.include?("t2"), "Executable Ruby files should be included"
-      refute cmds.include?("t3"),
-        "Executable files with a non Ruby extension shoudn't be included"
-      refute cmds.include?("t4"), "Non-executable files shouldn't be included"
-    end
-  end
-
-  def test_internal_command_path
-    assert_equal HOMEBREW_LIBRARY_PATH/"cmd/rbcmd.rb",
-                 Commands.path("rbcmd")
-    assert_equal HOMEBREW_LIBRARY_PATH/"cmd/shcmd.sh",
-                 Commands.path("shcmd")
-    assert_nil Commands.path("idontexist1234")
-  end
-
-  def test_internal_dev_command_path
-    assert_equal HOMEBREW_LIBRARY_PATH/"dev-cmd/rbdevcmd.rb",
-                 Commands.path("rbdevcmd")
-    assert_equal HOMEBREW_LIBRARY_PATH/"dev-cmd/shdevcmd.sh",
-                 Commands.path("shdevcmd")
-  end
-end