Simplify, avoid extra exceptions and add test for concurrent mspec mkdir_p

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58958 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/mspec/lib/mspec/helpers/fs.rb

@@ -17,16 +17,19 @@ class Object
     parts.each do |part|
       name = File.join name, part
 
-      stat = File.stat name rescue nil
-      if stat and stat.file?
+      if File.file? name
         raise ArgumentError, "path component of #{path} is a file"
       end
 
-      unless stat and stat.directory?
+      unless File.directory? name
         begin
           Dir.mkdir name
-        rescue Errno::EEXIST
-          raise unless File.directory? name
+        rescue Errno::EEXIST => e
+          if File.directory? name
+            # OK, another process/thread created the same directory
+          else
+            raise e
+          end
         end
       end
     end

spec/mspec/spec/helpers/fs_spec.rb

@@ -93,6 +93,19 @@ describe Object, "#mkdir_p" do
     File.open(@dir1, "w") { |f| }
     lambda { mkdir_p @dir2 }.should raise_error(ArgumentError)
   end
+
+  it "works if multiple processes try to create the same directory concurrently" do
+    original = File.method(:directory?)
+    File.should_receive(:directory?).at_least(:once) { |dir|
+      ret = original.call(dir)
+      if !ret and dir == @dir1
+        Dir.mkdir(dir) # Simulate race
+      end
+      ret
+    }
+    mkdir_p @dir1
+    original.call(@dir1).should be_true
+  end
 end
 
 describe Object, "#rm_r" do