add query scopes to message handler

fixes: PLAT-649

test-plan
*specs should pass

Change-Id: I1902a1e5ad516ee544d1981b2ba56b35cce45691
Reviewed-on: https://gerrit.instructure.com/41262
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Nathan Mills <nathanm@instructure.com>
QA-Review: Nathan Mills <nathanm@instructure.com>
Reviewed-by: Brad Humphrey <brad@instructure.com>

app/models/lti/message_handler.rb

@@ -28,5 +28,12 @@ module Lti
 
     validates_presence_of :message_type, :resource_handler, :launch_path
 
+    scope :by_message_types, lambda { |*message_types| where('lti_message_handlers.message_type IN (?)', message_types) }
+
+    scope :for_context, lambda { |context|
+      tool_proxies = ToolProxy.find_active_proxies_for_context(context)
+      joins(:resource_handler).where('lti_resource_handlers.tool_proxy_id' => tool_proxies)
+    }
+
   end
 end

spec/models/lti/message_handler_spec.rb

@@ -21,6 +21,9 @@ require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper.rb')
 module Lti
   describe MessageHandler do
 
+    let (:account) { Account.create }
+    let (:product_family) { ProductFamily.create(vendor_code: '123', product_code: 'abc', vendor_name: 'acme', root_account: account) }
+
     describe 'validations' do
       before(:each) do
         subject.message_type = 'message_type'
@@ -45,9 +48,80 @@ module Lti
         subject.save
         subject.errors.first.should == [:resource_handler, "can't be blank"]
       end
+    end
+
+    describe 'scope #message_type' do
+
+      it 'returns all message_handlers for a message_type' do
+        mh1 = create_message_handler
+        mh2 = create_message_handler
+        mh3 = create_message_handler(create_resource_handler, message_type: 'content_item')
+
+        message_handlers = described_class.by_message_types('basic-lti-launch-request')
+        message_handlers.count.should == 2
+      end
+
+      it 'returns all message_handlers for mutlipe message types' do
+        rh = create_resource_handler
+        mh1 = create_message_handler(rh)
+        mh2 = create_message_handler(rh, message_type: 'other_type')
+        mh3 = create_message_handler(rh, message_type: 'content_item')
+
+        message_handlers = described_class.by_message_types('basic-lti-launch-request', 'other_type')
+        message_handlers.count.should == 2
+      end
+
+    end
+
+    describe 'scope #for_tool_proxies' do
+
+
+      it 'returns all message_handlers for a tool proxy' do
+        tp = create_tool_proxy
+        tp.bindings.create(context: account)
+        message_handlers = (1..3).map do |code|
+          rh = create_resource_handler(tp, resource_type_code: code)
+          create_message_handler(rh)
+        end
+        Set.new(described_class.for_context(account)).should == Set.new(message_handlers)
+      end
+
+      it 'returns all message_handlers for multiple tool_proxy' do
+        tool_proxies = (1..3).map {|_| create_tool_proxy}
+        message_handlers = tool_proxies.map do |tp|
+          tp.bindings.create(context: account)
+          rh = create_resource_handler(tp)
+          create_message_handler(rh)
+        end
+        Set.new(described_class.for_context(account)).should == Set.new(message_handlers)
+      end
 
     end
 
 
+    def create_tool_proxy(opts = {})
+      default_opts = {
+        context: account,
+        shared_secret: 'shared_secret',
+        guid: SecureRandom.uuid,
+        product_version: '1.0beta',
+        lti_version: 'LTI-2p0',
+        product_family: product_family,
+        workflow_state: 'active',
+        raw_data: 'some raw data'
+      }
+      ToolProxy.create(default_opts.merge(opts))
+    end
+
+    def create_resource_handler(tool_proxy = create_tool_proxy, opts = {})
+      default_opts = {resource_type_code: 'code', name: 'resource name', tool_proxy: tool_proxy}
+      ResourceHandler.create(default_opts.merge(opts))
+    end
+
+    def create_message_handler(resource_handler = create_resource_handler, opts = {})
+      default_ops = {message_type: 'basic-lti-launch-request', launch_path: 'https://samplelaunch/blti', resource_handler: resource_handler}
+      MessageHandler.create(default_ops.merge(opts))
+    end
+
   end
 end