Gists for this blog post: http://inside.oib.com/writing-readable-rspec-examples/

bad_nesting_example_spec.rb

describe User do
  describe "#serialize_comments" do
    before do
      subject.stub(:read_comment_count).and_return(3)
      subject.stub(:unread_comment_count).and_return(5)
    end

    it "does something when there are 5 unread comments"
  end
end

bad_sentences_example_spec.rb

describe User do
  describe "permissions" do
    context "super user" do
      it "can see some widget"
    end
  end
end

good_nesting_example_spec.rb

describe User do
  describe "#serialize_comments" do
    context "when there are 5 unread comments" do
      before do
        subject.stub(:read_comment_count).and_return(3)
        subject.stub(:unread_comment_count).and_return(5)
      end

      it "does something when there are 5 unread comments"
    end
  end
end

good_sentences_example_spec.rb

describe User do
  describe "#allowed?" do
    context "as a super user" do
      it "can see some widget"
    end
  end
end