Add unique constraint for life cycle step definition name

app/models/project/life_cycle_step_definition.rb

@@ -35,7 +35,7 @@ class Project::LifeCycleStepDefinition < ApplicationRecord
   has_many :projects, through: :life_cycle_steps
   belongs_to :color, optional: false
 
-  validates :name, presence: true
+  validates :name, presence: true, uniqueness: true
   validates :type, inclusion: { in: %w[Project::StageDefinition Project::GateDefinition], message: :must_be_a_stage_or_gate }
   validate :validate_type_and_class_name_are_identical
 

db/migrate/20241217190533_add_uniqueness_index_to_project_life_cycle_step_definitions_name.rb

@@ -0,0 +1,5 @@
+class AddUniquenessIndexToProjectLifeCycleStepDefinitionsName < ActiveRecord::Migration[7.1]
+  def change
+    add_index :project_life_cycle_step_definitions, :name, unique: true
+  end
+end

spec/models/project/life_cycle_step_definition_spec.rb

@@ -40,6 +40,15 @@
   end
 
   describe "validations" do
+    it { is_expected.to validate_presence_of(:name) }
+    it { is_expected.to validate_uniqueness_of(:name) }
+
+    it {
+      expect(subject).to validate_inclusion_of(:type)
+        .in_array(%w[Project::StageDefinition Project::GateDefinition])
+        .with_message(:must_be_a_stage_or_gate)
+    }
+
     it "is invalid if type and class name do not match" do
       subject.type = "Project::GateDefinition"
       expect(subject).not_to be_valid