Use 'update!' to surface save errors

Previously we switched from 'update_attribute' to 'update' to fix
linting issues, but this carries a risk of silently failing to save
changes, since 'update' will run validations. This switches all uses
of 'update' to 'update!' to ensure we become aware of any issues in
case they are not covered by the tests.

.rubocop.yml

@@ -6,3 +6,11 @@ inherit_gem:
 inherit_mode:
   merge:
     - Exclude
+
+# We seldom check the return value of 'update' to see if
+# the operation was successful. Since we assume success, we
+# should raise an exception if this is not the case.
+#
+# We intend to add this to rubocop-govuk.
+Rails/SaveBang:
+  Enabled: true

app/models/link.rb

@@ -75,7 +75,7 @@ def self.build(params)
 
   def make_missing
     self.url = nil
-    save
+    save!
   end
 
 private

lib/tasks/import/covid19_mhclg.rake

@@ -26,7 +26,7 @@ namespace :import do
     end
 
     SERVICE_MAPPINGS.each do |type, codes|
-      service_interaction = ServiceInteraction.find_or_create_by(
+      service_interaction = ServiceInteraction.find_or_create_by!(
         service: Service.find_by!(lgsl_code: codes[:lgsl]),
         interaction: Interaction.find_by!(lgil_code: codes[:lgil]),
       )

lib/tasks/import/covid19_theyhelpyou.rake

@@ -14,7 +14,7 @@ namespace :import do
       end
 
       puts "Fetching mappings for type #{type}, LGSL=#{codes[:lgsl]} LGIL=#{codes[:lgil]}"
-      service_interaction = ServiceInteraction.find_or_create_by(
+      service_interaction = ServiceInteraction.find_or_create_by!(
         service: Service.find_by!(lgsl_code: codes[:lgsl]),
         interaction: Interaction.find_by!(lgil_code: codes[:lgil]),
       )

spec/features/links/index_spec.rb

@@ -1,6 +1,6 @@
 feature "The broken links page" do
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
 
     @service = create(:service, :all_tiers)
     @service_interaction = create(:service_interaction, service: @service)

spec/features/links/links_spec.rb

@@ -1,6 +1,6 @@
 feature "The links for a local authority" do
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
     @time = Timecop.freeze("2016-07-14 11:34:09 +0100")
     @local_authority = create(:local_authority, status: "ok", link_last_checked: @time - (60 * 60))
     @service = create(:service)

spec/features/local_authorities/local_authority_index_spec.rb

@@ -1,6 +1,6 @@
 feature "The local authorities index page" do
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
 
     @angus = create(:local_authority, name: "Angus")
     @zorro = create(:local_authority, name: "Zorro Council", broken_link_count: 1)

spec/features/local_authorities/local_authority_show_spec.rb

@@ -2,7 +2,7 @@
   let!(:local_authority) { create(:district_council) }
 
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
     visit local_authority_path(local_authority_slug: local_authority.slug)
   end
 
@@ -26,7 +26,7 @@
 
     it "displays 'No link'" do
       local_authority.homepage_url = nil
-      local_authority.save
+      local_authority.save!
       visit local_authority_path(local_authority_slug: local_authority.slug)
       within(:css, ".page-title") do
         expect(page).to have_content("No link")
@@ -35,7 +35,7 @@
 
     it "does not display 'Link not checked'" do
       local_authority.homepage_url = nil
-      local_authority.save
+      local_authority.save!
       visit local_authority_path(local_authority_slug: local_authority.slug)
       within(:css, ".page-title") do
         expect(page).not_to have_content("Link not checked")

spec/features/services/service_index_spec.rb

@@ -1,6 +1,6 @@
 feature "The services index page" do
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
 
     @aardvark = create(:service, label: "Aardvark Wardens")
     @zebra = create(:service, label: "Zebra Fouling", broken_link_count: 1)

spec/features/services/service_show_spec.rb

@@ -1,6 +1,6 @@
 feature "The services show page" do
   before do
-    User.create(email: "[email protected]", name: "Test User", permissions: %w[signin])
+    User.create!(email: "[email protected]", name: "Test User", permissions: %w[signin])
 
     @service = create(:service, :all_tiers)
     service_interaction = create(:service_interaction, service: @service)

spec/lib/local-links-manager/link_resolver_spec.rb

@@ -37,7 +37,7 @@
       end
 
       it "returns nil if no service interaction exists" do
-        service_interaction.destroy
+        service_interaction.destroy!
 
         expect(link_resolver.resolve).to be_nil
       end
@@ -69,8 +69,7 @@
           end
 
           it "returns the link that is not for LGIL 8 if its LGIL is higher than 8" do
-            interaction2.update(lgil_code: 9)
-
+            interaction2.update!(lgil_code: 9)
             expect(link_resolver.resolve).to eq(link2)
           end
         end
@@ -85,7 +84,7 @@
         end
 
         it "returns the link if it is for LGIL 8" do
-          link.interaction.update(lgil_code: 8)
+          link.interaction.update!(lgil_code: 8)
 
           expect(link_resolver.resolve).to eq(link)
         end

spec/requests/api/link_spec.rb

@@ -92,8 +92,8 @@
     end
 
     it "responds without link details for unsupported lgsl and lgil combination" do
-      link.destroy
-      service_interaction.destroy
+      link.destroy!
+      service_interaction.destroy!
 
       get "/api/link?authority_slug=blackburn&lgsl=2&lgil=4"