diff --git a/spec/factories/expense.rb b/spec/factories/expense.rb
index 726d94d..d2db7cd 100644
--- a/spec/factories/expense.rb
+++ b/spec/factories/expense.rb
@@ -1,19 +1,20 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
-    factory :expense do
-      wedding
-      sequence(:name) { |i| "Expense #{i}" }
-      pricing_type { "fixed" }
-      amount { 100 }
-    end
-
-    trait :fixed do
-      pricing_type { "fixed" }
-    end
-
-    trait :per_person do
-      pricing_type { "per_person" }
-    end
+  factory :expense do
+    wedding
+    sequence(:name) { |i| "Expense #{i}" }
+    pricing_type { 'fixed' }
+    amount { 100 }
   end
-  
\ No newline at end of file
+
+  trait :fixed do
+    pricing_type { 'fixed' }
+  end
+
+  trait :per_person do
+    pricing_type { 'per_person' }
+  end
+end
diff --git a/spec/factories/group_affinities.rb b/spec/factories/group_affinities.rb
index bc57226..217f2a9 100644
--- a/spec/factories/group_affinities.rb
+++ b/spec/factories/group_affinities.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
   factory :group_affinity do
-    association :group_a, factory: :group
-    association :group_b, factory: :group
+    group_a factory: %i[group]
+    group_b factory: %i[group]
     discomfort { GroupAffinity::NEUTRAL }
   end
 end
diff --git a/spec/factories/groups.rb b/spec/factories/groups.rb
index ccd1156..659b125 100644
--- a/spec/factories/groups.rb
+++ b/spec/factories/groups.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
diff --git a/spec/factories/guest.rb b/spec/factories/guest.rb
index 28f3b80..5a81e22 100644
--- a/spec/factories/guest.rb
+++ b/spec/factories/guest.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
diff --git a/spec/factories/table_arrangement.rb b/spec/factories/table_arrangement.rb
index 693e68a..e91e807 100644
--- a/spec/factories/table_arrangement.rb
+++ b/spec/factories/table_arrangement.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
@@ -5,4 +7,3 @@ FactoryBot.define do
     wedding
   end
 end
-  
\ No newline at end of file
diff --git a/spec/factories/users.rb b/spec/factories/users.rb
index 2aa8a37..fd61bfa 100644
--- a/spec/factories/users.rb
+++ b/spec/factories/users.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do
diff --git a/spec/factories/weddings.rb b/spec/factories/weddings.rb
index 5a765a1..14f7d96 100644
--- a/spec/factories/weddings.rb
+++ b/spec/factories/weddings.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024 Manuel Bustillo
 
 FactoryBot.define do