Add tests for rejecting illegal file attributes

spec/concerns/file_parameters_spec.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+class Controller < AnonymousController
+  include FileParameters
+end
+
+describe FileParameters do
+  let(:controller) { Controller.new }
+  let(:hello_world) { FactoryBot.create(:hello_world) }
+
+  describe '#reject_illegal_file_attributes!' do
+    def file_accepted?(file)
+      files = [[0, FactoryBot.attributes_for(:file, context: hello_world, file_id: file.id)]]
+      filtered_files = controller.send(:reject_illegal_file_attributes, hello_world.id, files)
+      files.eql?(filtered_files)
+    end
+
+    describe 'accepts' do
+      it 'main file of the exercise' do
+        main_file = hello_world.files.find { |e| e.role = 'main_file' }
+        expect(file_accepted?(main_file)).to be true
+      end
+
+      it 'new file' do
+        new_file = FactoryBot.create(:file, context: hello_world)
+        expect(file_accepted?(new_file)).to be true
+      end
+    end
+
+    describe 'rejects' do
+      it 'file of different exercise' do
+        fibonacci = FactoryBot.create(:fibonacci, allow_file_creation: true)
+        other_exercises_file = FactoryBot.create(:file, context: fibonacci)
+        expect(file_accepted?(other_exercises_file)).to be false
+      end
+
+      it 'hidden file' do
+        hidden_file = FactoryBot.create(:file, context: hello_world, hidden: true)
+        expect(file_accepted?(hidden_file)).to be false
+      end
+
+      it 'read only file' do
+        read_only_file = FactoryBot.create(:file, context: hello_world, read_only: true)
+        expect(file_accepted?(read_only_file)).to be false
+      end
+
+      it 'non existent file' do
+        non_existent_file = FactoryBot.build(:file, context: hello_world, id: 42)
+        expect(file_accepted?(non_existent_file)).to be false
+      end
+    end
+  end
+end