Modules & assignments LTI tool selection shows 100 results

Also adds basic test coverage around Api.paginate

Fixes PLAT-1357

Test Plan:

1) Create a test course and add 100 LTI tools to it:
course = Course.find(15)

(1..100).each do |n|
  cet = ContextExternalTool.new(
    url: "https://www.example.com",
    name: "Tool ##{n}",
    shared_secret:"foo",
    consumer_key:"bar")
  cet.context = course
  cet.save!
end

2) Try to add an LTI tool to a module or as an
   assignment, see that you can see all 100 tools.


Change-Id: I9c59d2286f928ad726917e9e794967dcf6ffca9d
Reviewed-on: https://gerrit.instructure.com/73680
Tested-by: Jenkins
Reviewed-by: Cody Cutrer <cody@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Matthew Wheeler <mwheeler@instructure.com>

app/controllers/lti/lti_apps_controller.rb

@@ -35,8 +35,9 @@ module Lti
       if authorized_action(@context, @current_user, :update)
         placements = params['placements'] || []
         collection = AppLaunchCollator.bookmarked_collection(@context, placements)
+        pagination_args = {max_per_page: 100}
         respond_to do |format|
-          launch_defs = Api.paginate(collection, self, named_context_url(@context, :api_v1_context_launch_definitions_url, include_host: true))
+          launch_defs = Api.paginate(collection, self, named_context_url(@context, :api_v1_context_launch_definitions_url, include_host: true), pagination_args)
           format.json { render :json => AppLaunchCollator.launch_definitions(launch_defs, placements) }
         end
       end

app/views/shared/_select_content_dialog.html.erb

@@ -83,7 +83,7 @@
           <i class="icon-link"></i>
           <%= t :external_tool_notice, "Select a tool from the list below, or enter a URL for an external tool you already know is configured with Basic LTI to add a link to it to this *module*.", :wrapper => '<span class="holder_type">\1</span>' %>
         </div>
-        <a href="<%= context_url(@context, controller:'lti/lti_apps', action:'launch_definitions', :placements => lti_app_placements, :per_page => '50') %>" class="external_tools_url" style="display: none;">&nbsp;</a>
+        <a href="<%= context_url(@context, controller:'lti/lti_apps', action:'launch_definitions', :placements => lti_app_placements, :per_page => '100') %>" class="external_tools_url" style="display: none;">&nbsp;</a>
         <table>
           <tr>
             <td colspan="2">

lib/api.rb

@@ -257,10 +257,14 @@ module Api
     Setting.get('api_max_per_page', '50').to_i
   end
 
+  def self.per_page
+    Setting.get('api_per_page', '10').to_i
+  end
+
   def self.per_page_for(controller, options={})
-    per_page = controller.params[:per_page] || options[:default] || Setting.get('api_per_page', '10')
+    per_page_requested = controller.params[:per_page] || options[:default] || per_page
     max = options[:max] || max_per_page
-    [[per_page.to_i, 1].max, max.to_i].min
+    [[per_page_requested.to_i, 1].max, max.to_i].min
   end
 
   # Add [link HTTP Headers](http://www.w3.org/Protocols/9707-link-header.html) for pagination

spec/lib/api_spec.rb

@@ -716,7 +716,8 @@ describe Api do
       let(:collection) { [1, 2, 3] }
 
       it "should not raise Folio::InvalidPage for pages past the end" do
-        expect(Api.paginate(collection, controller, 'example.com', page: collection.size + 1, per_page: 1)).
+        controller = stub('controller', request: request, response: response, params: {per_page: 1})
+        expect(Api.paginate(collection, controller, 'example.com', page: collection.size + 1)).
           to eq []
       end
 
@@ -738,6 +739,42 @@ describe Api do
           to raise_error(Folio::InvalidPage)
       end
     end
+
+    describe "page size limits" do
+      let(:collection) { (1..101).to_a }
+
+      context "with no max_per_page argument" do
+        it "should limit to the default max_per_page" do
+          controller = stub('controller', request: request, response: response, params: {per_page: Api.max_per_page + 5})
+          expect(Api.paginate(collection, controller, 'example.com').size).
+            to eq Api.max_per_page
+        end
+      end
+
+      context "with no per_page parameter" do
+        it "should limit to the default per_page" do
+          controller = stub('controller', request: request, response: response, params: {})
+          expect(Api.paginate(collection, controller, 'example.com').size).
+            to eq Api.per_page
+        end
+      end
+
+      context "with per_page parameter > max_per_page argument" do
+        let(:controller) { stub('controller', request: request, response: response, params: {per_page: 100}) }
+        it "should take the smaller of the max_per_page arugment and the per_page param" do
+          expect(Api.paginate(collection, controller, 'example.com', {max_per_page: 75}).size).
+            to eq 75
+        end
+      end
+
+      context "with per_page parameter < max_per_page argument" do
+        let(:controller) { stub('controller', request: request, response: response, params: {per_page: 75}) }
+        it "should take the smaller of the max_per_page arugment and the per_page param" do
+          expect(Api.paginate(collection, controller, 'example.com', {max_per_page: 100}).size).
+            to eq 75
+        end
+      end
+    end
   end
 
   context ".build_links" do