[chore][pkg/stanza] Fix tests which leave files open (#28569)

`fileconsumer.Manager.poll` leaves files open so that the next poll
cycle can use them. In tests, the direct use of this function should be
accompanied by explicit action to clean up the files.

pkg/stanza/fileconsumer/file.go

@@ -67,16 +67,20 @@ func (m *Manager) Start(persister operator.Persister) error {
  return nil
 }
 
-// Stop will stop the file monitoring process
-func (m *Manager) Stop() error {
- m.cancel()
- m.wg.Wait()
+func (m *Manager) closeFiles() {
  for _, r := range m.previousPollFiles {
  r.Close()
  }
  for _, r := range m.knownFiles {
  r.Close()
  }
+}
+
+// Stop will stop the file monitoring process
+func (m *Manager) Stop() error {
+ m.cancel()
+ m.wg.Wait()
+ m.closeFiles()
  m.cancel = nil
  return nil
 }

pkg/stanza/fileconsumer/util_test.go

@@ -91,6 +91,9 @@ func buildTestManager(t *testing.T, cfg *Config, opts ...testManagerOption) (*Ma
  }
  input, err := cfg.Build(testutil.Logger(t), testEmitFunc(tmc.emitChan))
  require.NoError(t, err)
+ t.Cleanup(func() {
+ input.closeFiles()
+ })
  return input, tmc.emitChan
 }