Add ToS acceptance to customer endpoint

It's another read-only attribute.

Please note that JSON:API specifies a format of `date-time` which we
don't adhere to because it uses a `Z` in front of the timezone offset
which doesn't seem to be included in the default json serialisation.

So I didn't add the format and left it as simple `string`. Problem?

app/json_schemas/customer_schema.rb

@@ -14,6 +14,10 @@ class CustomerSchema < JsonApiSchema
       code: { type: :string, nullable: true, example: "BUYER1" },
       email: { type: :string, example: "alice@example.com" },
       allow_charges: { type: :boolean, example: false },
+      terms_and_conditions_accepted_at: {
+        type: :string, format: "date-time", nullable: true,
+        example: "2022-03-12T15:55:00.000+11:00",
+      },
     }
   end
 
@@ -25,6 +29,7 @@ class CustomerSchema < JsonApiSchema
     attributes.except(
       :id,
       :allow_charges,
+      :terms_and_conditions_accepted_at,
     )
   end
 

app/serializers/api/v1/customer_serializer.rb

@@ -4,7 +4,7 @@ module Api
   module V1
     class CustomerSerializer < BaseSerializer
       attributes :id, :enterprise_id, :first_name, :last_name, :code, :email,
-                 :allow_charges
+                 :allow_charges, :terms_and_conditions_accepted_at
 
       belongs_to :enterprise, links: {
         related: ->(object) {

spec/requests/api/v1/customers_spec.rb

@@ -5,7 +5,13 @@ require "swagger_helper"
 describe "Customers", type: :request do
   let!(:enterprise1) { create(:enterprise) }
   let!(:enterprise2) { create(:enterprise) }
-  let!(:customer1) { create(:customer, enterprise: enterprise1) }
+  let!(:customer1) {
+    create(
+      :customer,
+      enterprise: enterprise1,
+      terms_and_conditions_accepted_at: Time.zone.parse("2000-01-01"),
+    )
+  }
   let!(:customer2) { create(:customer, enterprise: enterprise1) }
   let!(:customer3) { create(:customer, enterprise: enterprise2) }
 
@@ -116,7 +122,8 @@ describe "Customers", type: :request do
 
         run_test! do
           expect(json_response[:data][:attributes]).to include(
-            allow_charges: false
+            allow_charges: false,
+            terms_and_conditions_accepted_at: nil,
           )
         end
       end
@@ -179,7 +186,14 @@ describe "Customers", type: :request do
         param(:id) { customer1.id }
         schema "$ref": "#/components/schemas/resources/customer"
 
-        run_test!
+        run_test! do
+          date_time_string =
+            json_response[:data][:attributes][:terms_and_conditions_accepted_at]
+          expect(date_time_string).to match /^2000-01-01T00:00:00.000[Z+-].*$/
+          expect(DateTime.parse(date_time_string)).to eq(
+            customer1.terms_and_conditions_accepted_at
+          )
+        end
       end
 
       response "404", "Not found" do

swagger/v1/swagger.yaml

@@ -63,6 +63,11 @@ components:
                   allow_charges:
                     type: boolean
                     example: false
+                  terms_and_conditions_accepted_at:
+                    type: string
+                    format: date-time
+                    nullable: true
+                    example: '2022-03-12T15:55:00.000+11:00'
                 required:
                 - id
                 - enterprise_id
@@ -71,6 +76,7 @@ components:
                 - code
                 - email
                 - allow_charges
+                - terms_and_conditions_accepted_at
               relationships:
                 type: object
                 properties:
@@ -137,6 +143,11 @@ components:
                     allow_charges:
                       type: boolean
                       example: false
+                    terms_and_conditions_accepted_at:
+                      type: string
+                      format: date-time
+                      nullable: true
+                      example: '2022-03-12T15:55:00.000+11:00'
                   required:
                   - id
                   - enterprise_id
@@ -145,6 +156,7 @@ components:
                   - code
                   - email
                   - allow_charges
+                  - terms_and_conditions_accepted_at
                 relationships:
                   type: object
                   properties: