Add can_self_consent_after_gillick_assessment?

This adds a method on the `Patient` model that can be used to determine
if a child can self-consent, following a competent Gillick assessment.

Jira-Issue: MAV-5915

Author: thomasleese

app/controllers/draft_consents_controller.rb

@@ -231,16 +231,10 @@ def is_who_step? = current_step == :who
   def set_new_or_existing_contact_options
     @new_or_existing_contact_options = []
 
-    is_gillick_competent =
-      @patient
-        .gillick_assessments
-        .order(created_at: :desc)
-        .for_session(@session)
-        .for_programme(@programme)
-        &.first
-        &.gillick_competent?
-
-    if is_gillick_competent
+    if @patient.can_self_consent_after_gillick_assessment?(
+         session: @session,
+         programme_type: @programme.type
+       )
       @new_or_existing_contact_options << NewOrExistingContactOption.new(
         value: "patient",
         label: "Child (Gillick competent)"

app/models/patient.rb

@@ -547,6 +547,15 @@ def show_year_group?(team:)
     end
   end
 
+  def can_self_consent_after_gillick_assessment?(session:, programme_type:)
+    gillick_assessments
+      .for_session(session)
+      .where(programme_type:)
+      .order(created_at: :desc)
+      &.first
+      &.gillick_competent? || false
+  end
+
   def programme_status(programme, academic_year:)
     # TODO: Update this method to accept the `programme_type` so that we can
     #  then determine the right programme variant from the `disease_types` on

spec/models/patient_spec.rb

@@ -908,6 +908,106 @@
     it { should eq("JD") }
   end
 
+  describe "#can_self_consent_after_gillick_assessment?" do
+    subject(:can_self_consent_after_gillick_assessment) do
+      patient.can_self_consent_after_gillick_assessment?(
+        session:,
+        programme_type: programme.type
+      )
+    end
+
+    let(:programme) { Programme.sample }
+    let(:session) { create(:session, programmes: [programme]) }
+    let(:patient) { create(:patient) }
+
+    context "when patient has no Gillick assessments" do
+      it { should be(false) }
+    end
+
+    context "when patient has a Gillick assessment for a different programme" do
+      before do
+        create(
+          :gillick_assessment,
+          :competent,
+          patient:,
+          programme_type: "hpv",
+          session:
+        )
+      end
+
+      let(:programme) { Programme.flu }
+
+      it { should be(false) }
+    end
+
+    context "when patient has a Gillick assessment for a different session" do
+      let(:other_session) { create(:session, programmes: [programme]) }
+
+      before do
+        create(
+          :gillick_assessment,
+          :competent,
+          patient:,
+          programme_type: programme.type,
+          session: other_session
+        )
+      end
+
+      it { should be(false) }
+    end
+
+    context "when patient has a not competent Gillick assessment" do
+      before do
+        create(
+          :gillick_assessment,
+          :not_competent,
+          patient:,
+          programme_type: programme.type,
+          session:
+        )
+      end
+
+      it { should be(false) }
+    end
+
+    context "when patient has a competent Gillick assessment" do
+      before do
+        create(
+          :gillick_assessment,
+          :competent,
+          patient:,
+          programme_type: programme.type,
+          session:
+        )
+      end
+
+      it { should be(true) }
+    end
+
+    context "when patient has multiple Gillick assessments" do
+      before do
+        create(
+          :gillick_assessment,
+          :not_competent,
+          patient:,
+          programme_type: programme.type,
+          session:
+        )
+        create(
+          :gillick_assessment,
+          :competent,
+          patient:,
+          programme_type: programme.type,
+          session:
+        )
+      end
+
+      it "returns the result of the most recent assessment" do
+        expect(can_self_consent_after_gillick_assessment).to be(true)
+      end
+    end
+  end
+
   describe "#has_patient_specific_direction?" do
     subject { patient.has_patient_specific_direction?(team:) }