add scope to allow selection of placements

fixes PLAT-656

test
*specs pass

Change-Id: I824bb17df3d20c89224d453c858237969a869a24
Reviewed-on: https://gerrit.instructure.com/41785
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brad Humphrey <brad@instructure.com>
Product-Review: Nathan Mills <nathanm@instructure.com>
QA-Review: Nathan Mills <nathanm@instructure.com>

app/models/context_external_tool.rb

@@ -508,6 +508,24 @@ class ContextExternalTool < ActiveRecord::Base
   scope :having_setting, lambda { |setting| setting ? joins(:context_external_tool_placements).
       where("context_external_tool_placements.placement_type = ?", setting) : scoped }
 
+  scope :placements, lambda { |*placements|
+    if placements
+      module_item_sql = if placements.include? 'module_item'
+                          "(context_external_tools.not_selectable IS NOT TRUE AND
+                           ((COALESCE(context_external_tools.url, '') <> '' ) OR
+                           (COALESCE(context_external_tools.domain, '') <> ''))) OR "
+                        else
+                          ''
+                        end
+      where(module_item_sql + 'EXISTS (
+              SELECT * FROM context_external_tool_placements
+              WHERE context_external_tools.id = context_external_tool_placements.context_external_tool_id
+              AND context_external_tool_placements.placement_type IN (?) )', placements || [])
+    else
+      scoped
+    end
+  }
+
   def self.find_for(id, context, type, raise_error=true)
     id = id[Api::ID_REGEX] if id.is_a?(String)
     unless id.present?

spec/models/context_external_tool_spec.rb

@@ -386,6 +386,44 @@ describe ContextExternalTool do
     end
   end
 
+  describe "placements" do
+
+    it 'returns multiple requested placements' do
+      tool1 = @course.context_external_tools.create!(:name => "First Tool", :url => "http://www.example.com", :consumer_key => "key", :shared_secret => "secret")
+      tool2 = @course.context_external_tools.new(:name => "Another Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool2.settings[:editor_button] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool2.save!
+      tool3 = @course.context_external_tools.new(:name => "Third Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool3.settings[:resource_selection] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool3.save!
+      ContextExternalTool.all_tools_for(@course).placements('module_item', 'resource_selection').to_a.should eql([tool1, tool3].sort_by(&:name))
+    end
+
+    it 'it only returns a single requested placements' do
+      tool1 = @course.context_external_tools.create!(:name => "First Tool", :url => "http://www.example.com", :consumer_key => "key", :shared_secret => "secret")
+      tool2 = @course.context_external_tools.new(:name => "Another Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool2.settings[:editor_button] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool2.save!
+      tool3 = @course.context_external_tools.new(:name => "Third Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool3.settings[:resource_selection] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool3.save!
+      ContextExternalTool.all_tools_for(@course).placements('resource_selection').to_a.should eql([tool3])
+    end
+
+    it "doesn't return not selectable tools placements for moudle_item" do
+      tool1 = @course.context_external_tools.create!(:name => "First Tool", :url => "http://www.example.com", :consumer_key => "key", :shared_secret => "secret")
+      tool2 = @course.context_external_tools.new(:name => "Another Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool2.settings[:editor_button] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool2.save!
+      tool3 = @course.context_external_tools.new(:name => "Third Tool", :consumer_key => "key", :shared_secret => "secret")
+      tool3.settings[:resource_selection] = {:url => "http://www.example.com", :icon_url => "http://www.example.com", :selection_width => 100, :selection_height => 100}.with_indifferent_access
+      tool3.not_selectable = true
+      tool3.save!
+      ContextExternalTool.all_tools_for(@course).placements('module_item').to_a.should eql([tool1])
+    end
+
+  end
+
   describe "find_integration_for" do
     it "should return nil if there are no matching integrations" do
       at  = @account.context_external_tools.create!(name: 'at', url: 'http://example.com', consumer_key: '12345', shared_secret: 'secret')