Sam Pierson's Blog

If RubyMine isn’t recognizing cucumber features, ensure the following:

Cucumber gem is attached to project: RM | Settings | Ruby SDK and Gems | Attach gems.
If you edited *.feature files in early version of RubyMine it may be mapped on Text file. So you should check that *.feature extension is mapped on “Cucumber scenario files” in [...]

How to setup focussed testing in RubyMine:
Place focused_test.rb  in the folder above your $RAILS_ROOT (so multiple projects can share it).
In RubyMine:
Preferences -> External Tools -> Add

Name: Focussed Test
Group: Whatever
Program: /usr/bin/ruby
Parameters: $ProjectFileDir$/../focused_test.rb -b –line $LineNumber$ -f "$FilePath$"
Working Directory: $ProjectFileDir$

Preferences -> KeyMap
Create a shortcut to the external tool. I use F10.

After a long search I figured out how to increase the memory available for RubyMine on MacOS:
In RubyMine.app/Contents/Info.plist
Find:

<key>VMOptions</key>
<string>-Xms16m -Xmx192m …

Xmx is maximum memory to use.