Fix flaky ndjson reader spec

spec/lib/gitlab/import_export/json/ndjson_reader_spec.rb

@@ -21,7 +21,7 @@ describe Gitlab::ImportExport::JSON::NdjsonReader do
   describe '#exist?' do
     subject { ndjson_reader.exist? }
 
-    context 'given valid dir_path', quarantine: 'https://gitlab.com/gitlab-org/gitlab/-/issues/213843' do
+    context 'given valid dir_path' do
       let(:dir_path) { fixture }
 
       it { is_expected.to be true }

spec/support/import_export/common_util.rb

@@ -15,15 +15,17 @@ module ImportExport
       export_path = [prefix, 'spec', 'fixtures', 'lib', 'gitlab', 'import_export', name].compact
       export_path = File.join(*export_path)
 
-      extract_archive(export_path, 'tree.tar.gz')
+      if File.exist?(File.join(export_path, 'tree.tar.gz'))
+        extract_archive(export_path, 'tree.tar.gz')
+      end
 
       allow_any_instance_of(Gitlab::ImportExport).to receive(:export_path) { export_path }
     end
 
     def extract_archive(path, archive)
-      if File.exist?(File.join(path, archive))
-        system("cd #{path}; tar xzvf #{archive} &> /dev/null")
-      end
+      output, exit_status = Gitlab::Popen.popen(["cd #{path}; tar xzf #{archive}"])
+
+      raise "Failed to extract archive. Output: #{output}" unless exit_status.zero?
     end
 
     def cleanup_artifacts_from_extract_archive(name, prefix = nil)
@@ -31,7 +33,7 @@ module ImportExport
       export_path = File.join(*export_path)
 
       if File.exist?(File.join(export_path, 'tree.tar.gz'))
-        system("cd #{export_path}; rm -fr tree &> /dev/null")
+        system("cd #{export_path}; rm -fr tree")
       end
     end