validating postcode specs

spec/models/location_spec.rb

@@ -0,0 +1,27 @@
+require "rails_helper"
+
+RSpec.describe Location, type: :model do
+  describe "#new" do
+    let(:location) { FactoryBot.build(:location) }
+
+    it "belongs to an organisation" do
+      expect(location.scheme).to be_a(Scheme)
+    end
+  end
+
+  describe "#validate_postcode" do
+    let(:location) { FactoryBot.build(:location) }
+    it "does not add an error if postcode is valid" do
+      location.postcode = "M1 1AE"
+      location.save
+      expect(location.errors).to be_empty
+    end
+
+    it "does add an error when the postcode is invalid" do
+      location.postcode = "invalid"
+      location.save
+      expect(location.errors).not_to be_empty
+      expect(location.errors["postcode"]).to include(match I18n.t("validations.postcode"))
+    end
+  end
+end