Add UUID + SESSION_ID validation check

This is a nonsensical case which causes an error.
As such it should be validated out.

Author: alistair-white-horne-tng

app/models/immunisation_import_row.rb

@@ -939,7 +939,15 @@ def validate_school_urn
 
   def validate_session_id
     if session_id.present?
-      if session_id.to_i.nil?
+      if uuid.present? &&
+           VaccinationRecord.find_by(
+             uuid: uuid.to_s
+           )&.sourced_from_nhs_immunisations_api?
+        errors.add(
+          session_id.header,
+          "A session ID cannot be provided for this record; this record was sourced from an external source."
+        )
+      elsif session_id.to_i.nil?
         errors.add(
           session_id.header,
           "The session ID is not recognised. Download the offline spreadsheet " \

spec/models/immunisation_import_row_spec.rb

@@ -794,6 +794,37 @@
       end
     end
 
+    context "vaccination in a session, but UUID matches a record sourced from NHS immunisations API" do
+      let(:data) do
+        {
+          "VACCINATED" => "Y",
+          "PROGRAMME" => "Flu",
+          "SESSION_ID" => 1,
+          "DATE_OF_VACCINATION" => "#{AcademicYear.current}0901",
+          "UUID" => "12345678-1234-1234-1234-123456789abc"
+        }
+      end
+
+      before do
+        create(
+          :vaccination_record,
+          programme: create(:programme, :flu),
+          uuid: "12345678-1234-1234-1234-123456789abc",
+          source: :nhs_immunisations_api
+        )
+      end
+
+      it "has errors" do
+        expect(immunisation_import_row).to be_invalid
+        expect(immunisation_import_row.errors["SESSION_ID"]).to eq(
+          [
+            "A session ID cannot be provided for this record; " \
+              "this record was sourced from an external source."
+          ]
+        )
+      end
+    end
+
     context "with valid fields for Flu" do
       let(:programmes) { [create(:programme, :flu)] }