users_credits/manager service, handle the case if user does not have a plan

app/services/users_credits/manager.rb

@@ -89,6 +89,8 @@ module UsersCredits
 
       private
         def _will_use_credits?
+          return false, 0 unless plan
+
           if machine_credit = plan.machine_credits.find_by(creditable_id: reservation.reservable_id)
             users_credit = user.users_credits.find_by(credit_id: machine_credit.id)
             already_used_hours = users_credit ? users_credit.hours_used : 0
@@ -122,6 +124,8 @@ module UsersCredits
 
       private
         def _will_use_credits?
+          return false, nil unless plan
+
           # if there is a training_credit defined for this plan and this training
           if training_credit = plan.training_credits.find_by(creditable_id: reservation.reservable_id)
             # if user has not used all the plan credits

test/services/users_credits_manager_test.rb

@@ -6,12 +6,28 @@ class UsersCreditsManagerTest < ActiveSupport::TestCase
     @training = Training.find(2)
     @plan = Plan.find(3)
     @user = User.joins(:subscriptions).find_by(subscriptions: { plan: @plan })
+    @user.users_credits.destroy_all
     @availability = @machine.availabilities.first
     @reservation_machine = Reservation.new(user: @user, reservable: @machine)
     @reservation_training = Reservation.new(user: @user, reservable: @training)
   end
 
   ## context machine reservation
+  test "machine reservation from user without subscribed plan" do
+    @user.subscriptions.destroy_all
+
+    @reservation_machine.assign_attributes(slots_attributes: [{
+      start_at: @availability.start_at, end_at: @availability.start_at + 1.hour, availability_id: @availability.id
+    }])
+    manager = UsersCredits::Manager.new(reservation: @reservation_machine)
+
+    assert_equal false, manager.will_use_credits?
+    assert_equal 0, manager.free_hours_count
+
+    assert_no_difference 'UsersCredit.count' do
+      manager.update_credits
+    end
+  end
 
   test "machine reservation without credit associated" do
     Credit.where(creditable: @machine).destroy_all
@@ -101,6 +117,18 @@ class UsersCreditsManagerTest < ActiveSupport::TestCase
 
   # context training reservation
 
+  test "training reservation from user without subscribed plan" do
+    @user.subscriptions.destroy_all
+
+    manager = UsersCredits::Manager.new(reservation: @reservation_training)
+
+    assert_equal false, manager.will_use_credits?
+
+    assert_no_difference 'UsersCredit.count' do
+      manager.update_credits
+    end
+  end
+
   test "training reservation without credit associated" do
     Credit.where(creditable: @training).destroy_all