2nd scenario

+ added a scenario for submitting the button with no text  in url field
+ simplified the visit when clause to be used with any url
+ edited create route redirect if url param is empty (backend validation
  for required URL field)
+ added when clause for clicking submit button
+ added then clause for current path/page

app.rb

@@ -19,6 +19,7 @@ class App < Roda
 
     r.post "create" do
       url = r.params['url']
+      if url.empty? then r.redirect '/' end
       if nil == links.filter(:url => url).first
         code = SecureRandom.urlsafe_base64 4
         links.insert(url: url, code: code) 

features/homepage.feature

@@ -5,7 +5,13 @@ Feature: Homepage
   Loading the homepage is the initial starting point for this tool
 
   Scenario: Homepage Loads with a form
-    Given I visit the homepage
+    Given I visit the '/' page
     Then I should see text "URL Shortener"
     And I should see a form field "url"
     And I should see a "Submit" button
+
+  Scenario: Submitting the form without entering a URL
+    Given I visit the '/' page
+    When I click the submit button
+    Then I should be on "/" page
+

features/step_definitions/steps.rb

@@ -1,12 +1,14 @@
 # GIVEN
 
-Given('I visit the homepage') do
-  visit '/'
+Given('I visit the {string} page') do |string|
+  visit string
 end
 
 # WHEN
 
-
+When('I click the submit button') do 
+  click_button "Submit"
+end
 
 # THEN
 
@@ -21,3 +23,7 @@ end
 Then('I should see a {string} button') do |string|
   page.should have_button string
 end
+
+Then('I should be on {string} page') do |string|
+  page.should have_current_path string
+end