Add life cycle step increasing dates validation to the ProjectLifeCyc…

…leStep::BaseContract

app/contracts/project_life_cycle_steps/base_contract.rb

@@ -29,11 +29,47 @@
 module ProjectLifeCycleSteps
   class BaseContract < ::ModelContract
     validate :select_custom_fields_permission
+    validate :consecutive_steps_have_increasing_dates
 
     def select_custom_fields_permission
       return if user.allowed_in_project?(:edit_project_stages_and_gates, model)
 
       errors.add :base, :error_unauthorized
     end
+
+    def consecutive_steps_have_increasing_dates
+      # Filter out steps with missing dates before proceeding with comparison
+      filtered_steps = model.available_life_cycle_steps.select(&:start_date)
+
+      # Only proceed with comparisons if there are at least 2 valid steps
+      return if filtered_steps.size < 2
+
+      # Compare consecutive steps in pairs
+      filtered_steps.each_cons(2) do |previous_step, current_step|
+        if start_date_for(current_step) <= end_date_for(previous_step)
+          step = previous_step.is_a?(Project::Stage) ? "Stage" : "Gate"
+          field = current_step.is_a?(Project::Stage) ? :date_range : :date
+          model.errors.import(
+            current_step.errors.add(field, :non_continuous_dates, step:),
+            attribute: :"available_life_cycle_steps.#{field}"
+          )
+        end
+      end
+    end
+
+    private
+
+    def start_date_for(step)
+      step.start_date
+    end
+
+    def end_date_for(step)
+      case step
+      when Project::Gate
+        step.date
+      when Project::Stage
+        step.end_date || step.start_date # Use the start_date as fallback for single date stages
+      end
+    end
   end
 end

config/locales/en.yml

@@ -1198,10 +1198,13 @@ en:
               end_date_not_allowed: "Cannot assign end date to a Project::Gate"
             type:
               type_and_class_name_mismatch: "must be a Project::Gate"
+            date:
+              non_continuous_dates: "can’t be earlier than the previous %{step}'s end date."
         project/stage:
           attributes:
             date_range:
-              start_date_must_be_before_end_date: "Start date must be before the end date"
+              start_date_must_be_before_end_date: "start date must be before the end date."
+              non_continuous_dates: "can’t be earlier than the previous %{step}'s end date."
             type:
               type_and_class_name_mismatch: "must be a Project::Stage"
         query:

spec/contracts/project_life_cycle_steps/base_contract_spec.rb

@@ -34,27 +34,111 @@
 RSpec.describe ProjectLifeCycleSteps::BaseContract do
   include_context "ModelContract shared context"
 
-  let(:contract) { described_class.new(project_life_cycle_step, user) }
-  let(:user) { build_stubbed(:admin) }
-  let(:project_life_cycle_step) { build_stubbed(:project_gate) }
+  let(:contract) { described_class.new(project, user) }
+  let(:project) { build_stubbed(:project) }
 
   context "with authorised user" do
     let(:user) { build_stubbed(:user) }
+    let(:project) { build_stubbed(:project, available_life_cycle_steps: steps) }
+    let(:steps) { [] }
 
     before do
       mock_permissions_for(user) do |mock|
-        mock.allow_in_project(:edit_project_stages_and_gates, project: project_life_cycle_step.project)
+        mock.allow_in_project(:edit_project_stages_and_gates, project:)
       end
     end
 
     it_behaves_like "contract is valid"
+    include_examples "contract reuses the model errors"
+
+    describe "validations" do
+      describe "#consecutive_steps_have_increasing_dates" do
+        let(:step1) { build_stubbed(:project_gate, start_date: Date.new(2024, 1, 1)) }
+        let(:step2) { build_stubbed(:project_stage, start_date: Date.new(2024, 2, 1), end_date: Date.new(2024, 2, 28)) }
+        let(:step3) { build_stubbed(:project_gate, start_date: Date.new(2024, 3, 1), end_date: Date.new(2024, 3, 15)) }
+        let(:steps) { [step1, step2, step3] }
+
+        context "when no steps are present" do
+          let(:steps) { [] }
+
+          it_behaves_like "contract is valid"
+        end
+
+        context "when only one step is present" do
+          let(:steps) { [step1] }
+
+          it_behaves_like "contract is valid"
+        end
+
+        context "when steps have valid and increasing dates" do
+          let(:steps) { [step1, step2] }
+
+          it_behaves_like "contract is valid"
+        end
+
+        context "when steps have decreasing dates" do
+          context "and the erroneous step is a Gate" do
+            let(:steps) { [step3, step1] }
+
+            it_behaves_like "contract is invalid",
+                            "available_life_cycle_steps.date": :non_continuous_dates
+
+            it "adds an error to the decreasing step" do
+              contract.validate
+              expect(step1.errors.symbols_for(:date)).to include(:non_continuous_dates)
+            end
+          end
+
+          context "and the erroneous step is a Stage" do
+            let(:steps) { [step3, step2] }
+
+            it_behaves_like "contract is invalid",
+                            "available_life_cycle_steps.date_range": :non_continuous_dates
+
+            it "adds an error to the decreasing step" do
+              contract.validate
+              expect(step2.errors.symbols_for(:date_range)).to include(:non_continuous_dates)
+            end
+          end
+        end
+
+        context "when steps with identical dates" do
+          let(:step4) { build_stubbed(:project_gate, start_date: Date.new(2024, 1, 1)) }
+          let(:steps) { [step1, step4] }
+
+          it_behaves_like "contract is invalid",
+                          "available_life_cycle_steps.date": :non_continuous_dates
+        end
+
+        context "when a step has missing start dates" do
+          let(:step_missing_dates) { build_stubbed(:project_stage, start_date: nil, end_date: nil) }
+
+          context "and the other steps have increasing dates" do
+            let(:steps) { [step1, step_missing_dates, step2] }
+
+            it_behaves_like "contract is invalid",
+                            "available_life_cycle_steps.date_range": :blank
+          end
+
+          context "and the other steps have decreasing dates" do
+            let(:steps) { [step2, step_missing_dates, step1] }
+
+            it_behaves_like "contract is invalid",
+                            "available_life_cycle_steps.date": :non_continuous_dates
+
+            it "adds an error to the decreasing step" do
+              contract.validate
+              expect(step1.errors.symbols_for(:date)).to include(:non_continuous_dates)
+            end
+          end
+        end
+      end
+    end
   end
 
   context "with unauthorised user" do
     let(:user) { build_stubbed(:user) }
 
-    it_behaves_like "contract is invalid", base: :error_unauthorized
+    it_behaves_like "contract user is unauthorized"
   end
-
-  include_examples "contract reuses the model errors"
 end