title: What defines a "complete" Luigi task?
body: <p>I am working on building my first Luigi pipeline, and I am currently testing tasks individually before building my dependencies. During testing, I am using a version of the following main method to build a task:</p>
  
  <pre><code>if __name__ == "__main__":
  
      headers = dict()
      headers["Content-Type"] = "application/json"
      headers["Accept"] = "application/json"
  
      luigi.build[(CSVValidator(jsonfile = '/sample_input/sample_csv.json',
                  docfile = None,
                  error_limit = 2,
                  order_fields = 3,
                  output_file = 'validation_is_us.txt',
                  header = headers)])
  
      luigi.run()
  </code></pre>
  
  <p>This is what my csv_validator looks like:</p>
  
  <pre><code>class CSVValidator(luigi.Task):
      jsonfile = luigi.Parameter()
      docfile = luigi.Parameter()
      error_limit = luigi.Parameter()
      order_fields = luigi.Parameter()
      output_file = luigi.Parameter()
      header = luigi.DictParameter()
  
      def output(self):
          return luigi.LocalTarget(self.output_file + "/csv_validator_data_%s.txt" % time.time())
  
      def run(self):
          output_file = self.output().open('w')
          files = {}
          data = {}
          files["jsonfile"] = open(self.jsonfile, 'rb')
          files["docfile"] = open(self.docfile, 'rb')
          data["error_limit"] = self.error_limit
          data["order_fields"] = self.order_fields
          r = requests.post(*****~~~~~*****~~~~~,
                        headers=headers,
                        data=data, files=files)
          task_response = r.text.encode(encoding="UTF-8")
          print type(task_response)
          print(task_response)
          jsontaskdata = json.loads(task_response)
          json.dump(jsontaskdata, output_file)
          print("validated")
          output_file.close()
  </code></pre>
  
  <p>This task, however, is never actually run. Instead the luigi central scheduler claims that this task is already complete:</p>
  
  <pre><code>===== Luigi Execution Summary =====
  
  Scheduled 2 tasks of which:
  * 1 complete ones were encountered:
      - 1 CSVValidator(...)
  * 1 ran successfully:
      - 1 Downloader(...)
  </code></pre>
  
  <p>This progress looks :) because there were no failed tasks or missing dependencies</p>
  
  <p>Other tasks I have created, Downloader for example, do run successfully every time. What defines a complete task here? I don't understand what it means.</p>
  
  <p>Thanks for your time! </p>