Creating test objects in RSpec with FactoryGirl fails with Nested Attributes

I have a Workout model that has many PerformedExercises, which has many PeformedSets. I can't get it to build an object in my test and I am not sure if it's SQLite3, or something else (it works fine outside of the testing environment).

I have the following factories:

FactoryGirl.define do
 factory :workout do
   title    'workout one'
   performed_exercise
 end

 factory :performed_exercise do
  exercise_id       '2'
  performed_set
 end

 factory :performed_set do
  set_number        '1'
 end
end

My RSpec test looks like so (I've开发者_高级运维 made it real simple so as to rule out any other issues inside the test):

it "is causing me to lose hair" do
  wrkt = FactoryGirl.build(:workout)
end

When I run the test, I get the following error message:

Failure/Error: wrkt = FactoryGirl.build(:workout)
     ActiveRecord::StatementInvalid:
       SQLite3::ConstraintException: constraint failed: 
        INSERT INTO "performed_sets" ("created_at", "notes", "performed_exercise_id", "reps", "set_number", "updated_at", "weight") 
        VALUES (?, ?, ?, ?, ?, ?, ?)

Any help would be greatly appreciated!

Don't set the exercise id. Let SQLite handle the id's for you.

factory :performed_exercise do
  performed_set
end