Add error_tracking_api_url validations and tests

app/models/application_setting.rb

@@ -598,6 +598,7 @@ def self.kroki_formats_attributes
     inclusion: { in: [true, false], message: _('must be a boolean value') }
   validates :error_tracking_api_url,
     presence: true,
+    addressable_url: true,
     length: { maximum: 255 },
     if: :error_tracking_enabled?
 

spec/models/application_setting_spec.rb

@@ -1073,6 +1073,27 @@ def expect_invalid
         is_expected.to validate_numericality_of(:metrics_method_call_threshold).is_greater_than_or_equal_to(0)
       end
     end
+
+    context 'error tracking settings' do
+      context 'with error tracking disabled' do
+        before do
+          setting.error_tracking_enabled = false
+        end
+
+        it { is_expected.to allow_value(nil).for(:error_tracking_api_url) }
+      end
+
+      context 'with error tracking enabled' do
+        before do
+          setting.error_tracking_enabled = true
+        end
+
+        it { is_expected.to allow_value(http).for(:error_tracking_api_url) }
+        it { is_expected.to allow_value(https).for(:error_tracking_api_url) }
+        it { is_expected.not_to allow_value(ftp).for(:error_tracking_api_url) }
+        it { is_expected.to validate_presence_of(:error_tracking_api_url) }
+      end
+    end
   end
 
   context 'restrict creating duplicates' do