Add tests

spec/models/sales_log_spec.rb

@@ -978,5 +978,54 @@ RSpec.describe SalesLog, type: :model do
       end
     end
   end
+
+  describe "#child_under_16_constraints!" do
+    let(:sales_log) { create(:sales_log, saledate: Time.zone.local(2024, 4, 1)) }
+
+    it "sets ecstat2 to 9 when age2 is under 16" do
+      sales_log.age2 = 14
+      sales_log.set_derived_fields!
+      expect(sales_log.ecstat2).to eq(9)
+    end
+
+    it "does not clear ecstat2 if it is not 9" do
+      sales_log.age2 = 22
+      sales_log.ecstat2 = 3
+      sales_log.set_derived_fields!
+      expect(sales_log.ecstat2).to eq(3)
+    end
+
+    it "clears ecstat3 if it is 9 and age3 is not under 16" do
+      sales_log.age3 = 22
+      sales_log.ecstat3 = 9
+      sales_log.set_derived_fields!
+      expect(sales_log.ecstat3).to be_nil
+    end
+
+    it "does not clear ecstat3 if it is not 9" do
+      sales_log.age3 = 22
+      sales_log.ecstat3 = 8
+      sales_log.set_derived_fields!
+      expect(sales_log.ecstat3).to eq(8)
+    end
+
+    context "when a user changes their answer" do
+      before do
+        sales_log.age2 = 14
+        sales_log.ecstat2 = 9
+      end
+
+      it "clears the working situation only when no longer a child under 16 and retains the new value" do
+        sales_log.set_derived_fields!
+        expect(sales_log.ecstat2).to eq(9)
+        sales_log.age2 = 22
+        sales_log.set_derived_fields!
+        expect(sales_log.ecstat2).to be_nil
+        sales_log.ecstat2 = 4
+        sales_log.set_derived_fields!
+        expect(sales_log.ecstat2).to eq(4)
+      end
+    end
+  end
 end
 # rubocop:enable RSpec/MessageChain