text: Title: Add unit tests for File Metrics Collector
  Body: /kind feature
  
  We should add unit test for our [File Metrics Collector](https://github.com/kubeflow/katib/tree/master/pkg/metricscollector/v1beta1/file-metricscollector) to verify log parsing. 
  That will help to avoid issues similar to: https://github.com/kubeflow/katib/issues/1754
  
  /help
  /good-first-issue
  
  ---
  
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