Add spec for SVN directory name containing @.

Library/Homebrew/test/unpack_strategy/subversion_spec.rb

@@ -1,22 +1,26 @@
 require_relative "shared_examples"
 
 describe UnpackStrategy::Subversion do
-  let(:repo) {
+  let(:repo) { mktmpdir }
-    mktmpdir.tap do |repo|
+  let(:working_copy) { mktmpdir }
-      system "svnadmin", "create", repo
-    end
-  }
-  let(:working_copy) {
-    mktmpdir.tap do |working_copy|
-      system "svn", "checkout", "file://#{repo}", working_copy
-
-      FileUtils.touch working_copy/"test"
-      system "svn", "add", working_copy/"test"
-      system "svn", "commit", working_copy, "-m", "Add `test` file."
-    end
-  }
   let(:path) { working_copy }
 
+  before(:each) do
+    system "svnadmin", "create", repo
+
+    system "svn", "checkout", "file://#{repo}", working_copy
+
+    FileUtils.touch working_copy/"test"
+    system "svn", "add", working_copy/"test"
+    system "svn", "commit", working_copy, "-m", "Add `test` file."
+  end
+
   include_examples "UnpackStrategy::detect"
   include_examples "#extract", children: ["test"]
+
+  context "when the directory name contains an '@' symbol" do
+    let(:working_copy) { mktmpdir(["", "@1.2.3"])  }
+
+    include_examples "#extract", children: ["test"]
+  end
 end