Update Broadcast Message features

- Removes redundant "Create a broadcast message" scenario that was
  entirely covered by the "Create a customized broadcast message"
  scenario.
- Adds "Edit an existing broadcast message" scenario
- Adds "Remove an existing broadcast message" scenario

features/admin/broadcast_messages.feature

@@ -2,20 +2,26 @@
 Feature: Admin Broadcast Messages
   Background:
     Given I sign in as an admin
-    And application already has admin messages
+    And application already has a broadcast message
     And I visit admin messages page
 
   Scenario: See broadcast messages list
     Then I should see all broadcast messages
 
-  Scenario: Create a broadcast message
-    When submit form with new broadcast message
-    Then I should be redirected to admin messages page
-    And I should see newly created broadcast message
-
   Scenario: Create a customized broadcast message
     When submit form with new customized broadcast message
     Then I should be redirected to admin messages page
     And I should see newly created broadcast message
     Then I visit dashboard page
     And I should see a customized broadcast message
+
+  Scenario: Edit an existing broadcast message
+    When I edit an existing broadcast message
+    And I change the broadcast message text
+    Then I should be redirected to admin messages page
+    And I should see the updated broadcast message
+
+  Scenario: Remove an existing broadcast message
+    When I remove an existing broadcast message
+    Then I should be redirected to admin messages page
+    And I should not see the removed broadcast message

features/steps/admin/broadcast_messages.rb

 class Spinach::Features::AdminBroadcastMessages < Spinach::FeatureSteps
   include SharedAuthentication
   include SharedPaths
-  include SharedAdmin
 
-  step 'application already has admin messages' do
+  step 'application already has a broadcast message' do
     FactoryGirl.create(:broadcast_message, :expired, message: "Migration to new server")
   end
 
@@ -11,12 +10,6 @@ class Spinach::Features::AdminBroadcastMessages < Spinach::FeatureSteps
     expect(page).to have_content "Migration to new server"
   end
 
-  step 'submit form with new broadcast message' do
-    fill_in 'broadcast_message_message', with: 'Application update from 4:00 CST to 5:00 CST'
-    select '2018', from: "broadcast_message_ends_at_1i"
-    click_button "Add broadcast message"
-  end
-
   step 'I should be redirected to admin messages page' do
     expect(current_path).to eq admin_broadcast_messages_path
   end
@@ -37,4 +30,25 @@ class Spinach::Features::AdminBroadcastMessages < Spinach::FeatureSteps
     expect(page).to have_content 'Application update from 4:00 CST to 5:00 CST'
     expect(page).to have_selector %(div[style="background-color: #f2dede; color: #b94a48"])
   end
+
+  step 'I edit an existing broadcast message' do
+    click_link 'Edit'
+  end
+
+  step 'I change the broadcast message text' do
+    fill_in 'broadcast_message_message', with: 'Application update RIGHT NOW'
+    click_button 'Update broadcast message'
+  end
+
+  step 'I should see the updated broadcast message' do
+    expect(page).to have_content "Application update RIGHT NOW"
+  end
+
+  step 'I remove an existing broadcast message' do
+    click_link 'Remove'
+  end
+
+  step 'I should not see the removed broadcast message' do
+    expect(page).not_to have_content 'Migration to new server'
+  end
 end