Fix checks_import_examples.rb when applied to non-importable classes

spec/models/application_model/checks_import_examples.rb

@@ -1,17 +1,8 @@
 RSpec.shared_examples 'ApplicationModel::ChecksImport' do
   subject { build(described_class.name.underscore, id: unused_id) }
-  let(:unused_id) { described_class.pluck(:id).max * 2 }
+  let(:unused_id) { (described_class.pluck(:id).max || 1) * 2 }
 
-  context 'when Setting.get("system_init_done") is true AND Setting.get("import_mode") is false' do
+  context 'when Setting.get("system_init_done") is false (regardless of import_mode)' do
-    before { Setting.set('system_init_done', true) }
-    before { Setting.set('import_mode', false) }
-
-    it 'prevents explicit setting of #id attribute' do
-      expect { subject.save }.to change { subject.id }
-    end
-  end
-
-  context 'when Setting.get("system_init_done") is false' do
     before { Setting.set('system_init_done', false) }
 
     it 'allows explicit setting of #id attribute' do
@@ -19,7 +10,18 @@ RSpec.shared_examples 'ApplicationModel::ChecksImport' do
     end
   end
 
-  context 'when Setting.get("import_mode") is true' do
+  context 'when Setting.get("system_init_done") is true' do
+    before { Setting.set('system_init_done', true) }
+
+    context 'and Setting.get("import_mode") is false' do
+      before { Setting.set('import_mode', false) }
+
+      it 'prevents explicit setting of #id attribute' do
+        expect { subject.save }.to change { subject.id }
+      end
+    end
+
+    context 'and Setting.get("import_mode") is true' do
       before { Setting.set('import_mode', true) }
 
       shared_examples 'importable classes' do
@@ -37,3 +39,4 @@ RSpec.shared_examples 'ApplicationModel::ChecksImport' do
       include_examples described_class.importable? ? 'importable classes' : 'non-importable classes'
     end
   end
+end