Merge pull request #2128 from reitermarkus/spec-unpack

Convert `brew unpack` test to spec.

Library/Homebrew/test/cmd/unpack_spec.rb

+describe "brew unpack", :integration_test do
+  it "unpacks a given Formula's archive" do
+    setup_test_formula "testball"
+
+    Dir.mktmpdir do |path|
+      path = Pathname.new(path)
+
+      shutup do
+        expect { brew "unpack", "testball", "--destdir=#{path}" }
+          .to be_a_success
+      end
+
+      expect(path/"testball-0.1").to be_a_directory
+    end
+  end
+end

Library/Homebrew/test/unpack_test.rb

-require "testing_env"
-
-class IntegrationCommandTestUnpack < IntegrationCommandTestCase
-  def test_unpack
-    setup_test_formula "testball"
-
-    mktmpdir do |path|
-      cmd "unpack", "testball", "--destdir=#{path}"
-      assert File.directory?("#{path}/testball-0.1"),
-        "The tarball should be unpacked"
-    end
-  end
-end